back to indexDr. Erich Jarvis: The Neuroscience of Speech, Language & Music | Huberman Lab Podcast #87
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Welcome to the Huberman Lab Podcast,
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where we discuss science and science-based tools
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for everyday life.
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I'm Andrew Huberman,
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and I'm a professor of neurobiology and ophthalmology
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at Stanford School of Medicine.
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Today, my guest is Dr. Eric Jarvis.
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Dr. Jarvis is a professor at the Rockefeller University
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in New York City, and his laboratory studies
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the neurobiology of vocal learning, language,
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speech disorders, and remarkably,
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the relationship between language, music, and movement,
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in particular, dance.
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His work spans from genomics,
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so the very genes that make up our genome,
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and the genomes of other species
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that speak and have language,
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such as songbirds and parrots,
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all the way up to neural circuits,
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that is the connections in the brain and body
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that govern our ability to learn and generate
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specific sounds and movements coordinated with those sounds,
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including hand movements,
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and all the way up to cognition,
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that is our ability to think in specific ways
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based on what we are saying
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and the way that we comprehend
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what other people are saying, singing, and doing.
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As you'll soon see, I was immediately transfixed
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and absolutely enchanted by Dr. Jarvis's description
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of his work and the ways that it impacts
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all the various aspects of our lives.
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For instance, I learned from Dr. Jarvis that as we read,
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we are generating very low levels
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of motor activity in our throat.
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That is, we are speaking the words that we are reading
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at a level below the perception of sound
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or our own perception of those words,
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but if one were to put an amplifier
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or to measure the firing of those muscles
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in our vocal cords,
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we'd find that as we're reading information,
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we are actually speaking that information.
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And as I learned and you'll soon learn,
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there's a direct link between those species in the world
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that have song and movement,
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which many of us would associate with dance,
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and our ability to learn and generate complex language.
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So for people with speech disorders like stutter
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or for people who are interested
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in multiple language learning,
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bilingual, trilingual, et cetera,
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and frankly, for anyone who is interested
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in how we communicate through words written or spoken,
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I'm certain today's episode is going to be
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an especially interesting and important one for you.
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Dr. Jarvis's work is so pioneering
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that he has been awarded truly countless awards.
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I'm not going to take our time
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to list off all the various important awards
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that he's received,
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but I should point out that in addition
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to being a decorated professor
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at the Rockefeller University,
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he is also an investigator
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with the Howard Hughes Medical Institute,
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the so-called HHMI.
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And for those of you that don't know,
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HHMI investigators are selected
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on an extremely competitive basis
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that they have to re-up,
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that is they have to re-compete every five years.
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They actually receive a grade every five years
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that dictates whether or not
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they are no longer a Howard Hughes investigator,
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whether or not they can advance
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to another five years of funding
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for their important research.
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And indeed, Howard Hughes investigators are selected
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not just for the rigor of their work,
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but for their pioneering spirit
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and their ability to take on high risk,
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high benefit work,
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which is exactly the kind of work
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that Dr. Jarvis has been providing for decades now.
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Again, I think today's episode
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is one of the more unique and special episodes
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that we've had on the Huberman Lab Podcast.
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I single it out because it really spans
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from the basic to the applied.
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And Dr. Jarvis's story is an especially unique one
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in terms of how he arrived at becoming a neurobiologist.
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So for those of you that are interested
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in personal journey and personal story,
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Dr. Jarvis's is truly a special and important one.
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I'm pleased to announce that the Huberman Lab Podcast
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is now partnered with Momentous Supplements.
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We partnered with Momentous for several important reasons.
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Again, that's livemomentous.com slash Huberman.
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Before we begin, I'd like to emphasize that this podcast
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is separate from my teaching and research roles at Stanford.
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It is, however, part of my desire and effort
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And now for my discussion with Dr. Eric Jarvis.
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Eric, so great to have you here.
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Very interested in learning from you
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about speech and language, and even as I asked the question,
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I realized that a lot of people, including myself,
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probably don't fully appreciate the distinction
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between speech and language, right?
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Speech I think of as the motor patterns,
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the production of sound that has meaning, hopefully,
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and language, of course, come in various languages
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and varieties of ways of communicating.
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But in terms of the study of speech and language
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and thinking about how the brain organizes
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speech and language, what are the similarities?
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What are the differences?
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How should we think about speech and language?
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Yeah, well, I'm glad you invited me here,
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and I'm also glad to get that first question,
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which I can consider a provocative one.
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The reason why, I've been struggling,
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what is the difference with speech and language
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for many years, and realize why am I struggling
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is because there are behavioral terms,
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let's call them psychology-developed kind of terms,
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that don't actually align exactly with brain function, right?
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And the question is,
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is there a distinction between speech and language?
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And when I look at the brain of work
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that other people have done, work we have done,
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also compared it with animal models,
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like those who can imitate sounds,
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like parrots and songbirds,
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I start to see there really isn't such a sharp distinction.
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So to get at what I think is going on,
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let me tell you how some people think of it now,
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that there's a separate language module in the brain
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that has all the algorithms and computations
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that influence the speech pathway on how to produce sound,
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and the auditory pathway on how to perceive and interpret it
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for speech or for sound that we call speech.
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And it turns out, I don't think there is any good evidence
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for a separate language module.
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Instead, there is a speech production pathway
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that's controlling our larynx, controlling our jaw muscles,
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that has built within it all the complex algorithms
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for spoken language, and there's the auditory pathway
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that has built within it all the complex algorithms
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for understanding speech,
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not separate from a language module.
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And this speech production pathway is specialized to humans
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and parrots and songbirds,
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whereas this auditory perception pathway
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is more ubiquitous amongst the animal kingdom,
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and this is why dogs can understand,
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sit, siente se, come here, boy, get the ball, and so forth.
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Dogs can understand several hundred human speech words.
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Great apes, you can teach them for several thousand,
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but they can't say a word.
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Because you've raised a number of animal species
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early on here, and because I have basically an obsession
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with animals since the time I was very small,
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I have to ask, which animals have language?
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Which animals have modes of communication
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that are sort of like language?
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You know, I've heard whale songs.
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I don't know what they're saying.
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They sound very beautiful,
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but they could be insulting each other for all I know.
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And they very well may be.
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Dolphins, birds, I mean, what do we understand
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about modes of communication that are like language
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but might not be what would classically be called language?
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Right, so modes of communication
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that people would define as language,
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more in a very narrow definition,
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they would say production of sound, so speech.
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But what about the hands, the gesturing with the hands?
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What about a bird who is doing aerial displays in the air,
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communicating information through body language, right?
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Well, I'm gonna go back to the brain.
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So what I think is going on is for spoken language,
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we're using the speech pathway
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in all the complex algorithms there.
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Next to the brain regions that are controlling
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spoken language are the brain regions
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or the brain regions for gesturing with the hands.
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And that hand parallel pathway
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has also complex algorithms that we can utilize.
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And some species are more advanced in these circuits,
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whether it's sound or gesturing with hands,
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and some are less advanced.
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Now, we humans and a few others are the most advanced
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for the speech sounds or the spoken language,
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but a non-human primate can produce gesturing
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in a more advanced form than they could produce sound.
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I'm not sure I got that across clearly,
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just to say that humans are the most advanced
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at spoken language, but not necessarily as big a difference
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at gestural language compared to some other species.
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Very clear and very interesting
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and immediately prompts the question,
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have there been brain imaging or other sorts of studies
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evaluating neural activity in the context of cultures
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and languages, at least that I associate
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with a lot of hand movement, like Italian versus,
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I don't know, maybe you could give us some examples
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of cultures where language is not associated
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with as much overt hand movement.
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Yes, so as you and I are talking here today
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and people who are listening but can't see us,
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we're actually gesturing with our hands as we talk
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without knowing it or doing it unconsciously.
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And if we were talking on a telephone,
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I would have one hand here and I'd be gesturing
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with the other hand without even you seeing me, right?
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And so why is that?
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Some have argued, and I would agree,
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based upon what we've seen,
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is that there's an evolutionary relationship
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between the brain pathways that control
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speech production and gesturing.
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And the brain regions I mentioned
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are directly adjacent to each other.
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I think that the brain pathways that control speech
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evolved out of the brain pathways
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that control body movement, all right?
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And that when you talk about Italian, French,
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English, and so forth, each one of those languages
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come with a learned set of gestures
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that you can communicate with.
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Now, how is that related to other animals?
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Well, Coco, a gorilla, who was raised with humans
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for 39 years or more, learned how to do gesture,
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communication, learned how to sign language,
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so to speak, right?
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But Coco couldn't produce those sounds.
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Coco could understand them as well
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by seeing somebody sign or hearing somebody produce speech.
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But Coco couldn't produce it with her voice.
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And so what's going on there is that a number of species,
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not all of them, a number of species
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have motor pathways in the brain
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where you can do learned gesturing,
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rudimentary language if you wanted, say, with your limbs,
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even if it's not as advanced as humans.
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But they don't have this extra brain pathway for the sound.
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So they can't gesture with their voice
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in the way that they gesture with their hands.
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One thing that I've wondered about for a very long time
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is whether or not primitive emotions
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and primitive sounds are the early substrate of language,
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and whether or not there's a bridge that we can draw
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between those in terms of just the basic respiration systems
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associated with different extreme feelings.
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Here's the way I'm imagining this might work.
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When I smell something delicious,
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I typically inhale more,
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and I might say, mm, or something like that.
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Whereas if I smell something putrid,
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I typically turn away, I wince,
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and I will exhale, or sort of kind of like turn away,
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trying to not ingest those molecules
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or inhale those molecules.
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I could imagine that these are the basic
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dark and light contrasts of the language system.
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And as I say that,
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I'm saying that from the orientation of a vision scientist
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who thinks of all visual images built up
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in a very basic way of a hierarchical model
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of the ability to see dark and light.
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So I could imagine this kind of primitive
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to more sophisticated pyramid of sound to language.
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Is this a crazy idea?
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Do we have any evidence this is the way it works?
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No, it's not a crazy idea.
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And in fact, you hit upon one of the key distinctions
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in the field of research that I had started out in,
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which is vocal learning research.
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So for vocal communication,
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you have most vertebrate species vocalize,
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but most of them are producing innate sounds
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that they're born with producing.
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That is babies crying, for example, or dogs barking.
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And only a few species have learned vocal communication,
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the ability to imitate sounds.
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And that is what makes spoken language special.
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When people think of what's special about language,
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it's the learned vocalizations.
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That is what's rare.
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And so this distinction between innateness and learned
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is more of a bigger dichotomy
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when it comes to vocalizations
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than for other behaviors in the animal kingdom.
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And when you go in the brain, you see it there as well.
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And so all the things you talked about,
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the breathing, the grunting, and so forth,
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a lot of that is handled by the brainstem circuits
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right around the level of your neck and below,
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like a reflex kind of thing.
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So, or even some emotional aspects of your behavior
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in the hypothalamus and so forth.
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But for a learned behavior, learning how to speak,
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learning how to play the piano,
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teaching a dog to learn how to do tricks
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is using the forebrain circuits.
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And what has happened is that there's a lot
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of forebrain circuits that are controlling
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learning how to move body parts in these species,
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but not for the vocalizations.
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But in humans and in parrots and some other species,
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somehow we acquired circuits where the forebrain
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has taken over the brainstem,
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and now using that brainstem not only to produce
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the innate behaviors or vocal behaviors,
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but the learned ones as well.
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Do we have any sense of when modern
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or sophisticated language evolved?
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Thinking back to the species that we evolved from
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and even within Homo sapiens,
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has there been an evolution of language?
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Has there been a devolution of language?
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Yeah, I would say, and to be able to answer that question,
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it does come with the caveat that I think we humans
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overrate ourselves when it compared to other species.
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And so it makes even scientists go astray
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in trying to hypothesize when you especially
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don't find fossil evidence of language that easily
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out there in terms of what happened in the past.
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We, amongst the primates, which we humans belong to,
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we are the only ones that have
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this advanced vocal learning ability.
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Now, when it was assumed that it was only Homo sapiens,
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then you can go back in time now based upon genomic data,
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not only of us living humans,
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but of the fossils that have been found for Homo sapiens,
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of Neanderthals, of Denisovan individuals,
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and discover that our ancestor, our human ancestors,
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supposedly hybridized with these other hominid species
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and it was assumed that these other hominid species
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don't learn how to imitate sounds.
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I don't know of any species today that's a vocal learner
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that can have children with a non vocal learning species.
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I don't see it, it doesn't mean it didn't exist.
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And when we look at the genetic data
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from these ancestral hominids that,
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where we can look at genes that are involved
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in learning vocal communication,
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they have the same sequence as we humans do
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for genes that function in speech circuits.
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So I think Neanderthals had spoken language.
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I'm not gonna say it's as advanced as what it is in humans,
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I don't know, but I think it's been there
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for at least between 500,000 to a million years
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that our ancestors had this ability
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and that we've been coming more and more advanced
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with it culturally and possibly genetically,
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but I think it's evolved so much
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that I think it's evolved sometime
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in the last 500,000 to a million years.
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Maybe we could talk a little bit more
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about the overlap between brain circuits
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that control language and speech in humans
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and other animals.
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I was weaned in the neuroscience era
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where bird song and the ability of birds
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to learn their tutor song was and still is
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a prominent field, subfield of neuroscience.
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And then of course, neuroimaging of humans,
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speaking and learning, et cetera.
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And this notion of a critical period,
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a time in which language is learned more easily
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than it is later in life.
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And the names of the different brain areas
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were quite different.
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One opens the textbooks, we hear Wernicke's and Broca's
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for the humans and you look at the birds,
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I remember, you know.
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Robust arch striatum area X.
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That's right, yes.
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But for most of our listeners,
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those names won't mean a whole lot.
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But in terms of homologies between areas
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in terms of function, what do we know?
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And how similar or different are the brain areas
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controlling speech and language in say,
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a songbird and a young human child?
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So going back to the 1950s and even a little earlier,
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Peter Mahler and others who got involved
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in neuroethology, the study of neurobiology
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of behavior in a natural way, right?
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You know, they start to find that behaviorally,
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there are these species of birds like songbirds and parrots
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and now we also know hummingbirds, just three of them
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out of the 40 something bird groups out there
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on the planet, orders, that they can imitate sounds
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And so that was the similarity.
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In other words, they had this kind of behavior
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that's more similar to us than chimpanzees have with us
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or than chickens have with them, right?
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They're close to relatives.
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And then they discovered even more similarities,
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these critical periods that if you remove a child,
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this unfortunately happens where a child is feral
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and is not raised with human and goes through
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their puberty phase of growth,
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it becomes hard for them to learn a language as an adult.
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So there's this critical period where you learn best.
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And even later on when you're in regular society,
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it's hard to learn.
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Well, the birds undergo the same thing.
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And then it was discovered that if they become deaf,
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we humans become deaf, our speech starts to deteriorate
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without any kind of therapy.
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If a non-human primate or let's say a chicken becomes deaf,
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their vocalizations don't deteriorate, very little at least.
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Well, this happens in the vocal learning birds.
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So there were all these behavioral parallels
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that came along in a package.
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And then people looked into the brain.
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Fernando Nadeva, my former PhD advisor,
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and began to discover the area X you talked about,
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the robust nucleus of the archipelium.
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And these brain pathways were not found
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in the species who couldn't imitate.
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So there was a parallel here.
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And then jumping many years later,
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I started to dig down into these brain circuits
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to discover that these brain circuits
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have parallel functions with the brain circuits for humans,
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even though they're by a different name
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like Broca's and laryngomotor cortex.
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And most recently, we discovered not only the actual
link |
circuitry and the connectivity are similar,
link |
but the underlying genes that are expressed
link |
in these brain regions in a specialized way,
link |
different from the rest of the brain are also similar
link |
between humans and songbirds and parrots.
link |
So all the way down to the genes,
link |
and now we're finding the specific mutations
link |
are also similar, not always identical, but similar,
link |
which indicates remarkable convergence
link |
for so-called complex behavior in species
link |
separated by 300 million years from the common ancestor.
link |
And not only that, we are discovering that mutations
link |
in these genes that cause speech deficits in humans,
link |
like in FOXP2, if you put those same mutations
link |
or similar type of deficits in these vocal learning birds,
link |
you get similar deficits.
link |
So convergence of the behavior is associated
link |
with similar genetic disorders of the behavior.
link |
I have to ask, do hummingbirds sing or do they hum?
link |
Hummingbirds hum with their wings
link |
and sing with their syrinx.
link |
In a coordinated way?
link |
In a coordinated way.
link |
There's some species of hummingbirds that actually will,
link |
Doug Ashford showed this, that will flap their wings
link |
and create a slapping sound with their wings
link |
that's in unison with their song.
link |
And you would not know it,
link |
but it sounds like a particular syllable in their songs,
link |
even though it's their wings
link |
and their voice at the same time.
link |
Hummingbirds are clapping to their song.
link |
Clapping, they're snapping their wings together
link |
in unison with a song to make it like,
link |
if I'm going, ba da da da da da, ba da,
link |
you know, and I banged on the table.
link |
Except they make it almost sound like their voice
link |
And they got some of the smallest-
link |
I guess as the kids would say, mind blown, right?
link |
Incredible, I love hummingbirds.
link |
And I always feel like it's such a special thing
link |
to get a moment to see one because they move around so fast
link |
and they flit away so fast in these ballistic trajectories
link |
that when you get to see one stationary for a moment
link |
or even just hovering there,
link |
you feel like you're extracting so much
link |
from their little microcosm of life.
link |
But now I realize they're playing music essentially.
link |
And what's amazing about hummingbirds
link |
and we're gonna say vocal learning species in general
link |
is that for whatever reason,
link |
they seem to evolve multiple complex traits.
link |
You know, this idea that the evolving language,
link |
spoken language in particular,
link |
comes along with a set of specializations.
link |
When I was coming up in neuroscience,
link |
I learned that, I think it was the work of Peter Marler,
link |
that young birds learn, songbirds, learn their tutor's song
link |
and learn it quite well,
link |
but that they could learn the song of another tutor.
link |
In other words, they could learn a different,
link |
and for the listeners, I'm doing air quotes here,
link |
a different language, a different bird song,
link |
different than their own species song,
link |
but never as well as they could learn
link |
their own natural genetically linked song.
link |
Genetically linked, meaning that it would be like
link |
me being raised in a different culture
link |
and that I would learn the other language,
link |
but not as well as I would have learned English.
link |
That is true, yes.
link |
And that's what I learned growing up as well
link |
and talked to Peter Marler himself about before he passed.
link |
Yeah, he used to call it
link |
the innate predisposition to learn.
link |
All right, so, which would be kind of the equivalent
link |
in the linguistic community of universal grammar.
link |
There is something genetically influencing
link |
our vocal communication on top of what we learn culturally.
link |
And so there is this balance between
link |
the genetic control of speech or a song in these birds
link |
and the learned cultural control.
link |
And so, yes, if you were to take, you know,
link |
I mean, in this case, we actually tried this
link |
at Rockefeller later on,
link |
take a zebra finch and raise it with a canary,
link |
it would sing a song that was sort of like
link |
a hybrid in between.
link |
We call it a keninch, right?
link |
And vice versa for the canary,
link |
because there's something different about their
link |
vocal musculature or the circuitry in the brain.
link |
And with a zebra finch,
link |
even with a closely related species,
link |
if you would take a zebra finch, a young animal,
link |
and in one cage next to it,
link |
place its own species, adult male, right?
link |
And in the other cage place a Bengalese finch next to it,
link |
it would preferably learn the song
link |
from its own species neighbor.
link |
But if you remove its neighbor,
link |
it would learn that Bengalese finch very well.
link |
So there's, it has something to do with also
link |
the social bonding with your own species.
link |
That raises a question that I based on something
link |
I also heard, but I don't have any scientific
link |
peer reviewed publication to point to,
link |
which is this idea of pigeon, not the bird,
link |
but this idea of when multiple cultures and languages
link |
converge in a given geographic area,
link |
that the children of all the different native languages
link |
will come up with their own language.
link |
I think this was in island culture,
link |
maybe in Hawaii called pigeon,
link |
which is sort of a hybrid of the various languages
link |
that their parents speak at home.
link |
And that they themselves speak.
link |
And that somehow pigeon, again, not the bird,
link |
but a language called pigeon for reasons I don't know,
link |
harbors certain basic elements of all language.
link |
I haven't studied enough myself
link |
in terms of pigeon specifically,
link |
but in terms of cultural evolution of language
link |
and hybridization between different cultures and so forth,
link |
even amongst birds with different dialects.
link |
And you bring them together.
link |
What is going on here is cultural evolution
link |
remarkably tracks genetic evolution.
link |
So if you bring people from two separate populations
link |
together that have been in their separate populations
link |
evolutionarily at least for hundreds of generations.
link |
So someone's speaking Chinese, someone's speaking English.
link |
And that child then is learning from both of them.
link |
Yes, that child is gonna be able to pick up
link |
and merge phonemes and words together
link |
in a way that an adult wouldn't.
link |
Because why they're experiencing both languages
link |
at the same time during their critical period years
link |
in a way that adults would not be able to experience.
link |
And so you get a hybrid.
link |
And the lowest common denominator
link |
is gonna be what they share.
link |
And so the phonemes that they've retained
link |
in each of their languages is what's gonna be,
link |
I imagine, used the most.
link |
So we've got brain circuits in songbirds and in humans
link |
that in many ways are similar,
link |
perhaps not in their exact wiring
link |
but in their basic contour of wiring.
link |
And genes that are expressed in both sets of neural circuits
link |
in very distinct species that are responsible
link |
for these phenomenon we're calling speech and language.
link |
What sorts of things are those genes controlling?
link |
I could imagine they were controlling
link |
the wiring of connections between brain areas,
link |
essentially a map of a circuit,
link |
basically like an engineer would design a circuit
link |
for speech and language,
link |
nature designed the circuit for speech and language.
link |
But presumably other things too,
link |
like the ability to connect motor patterns
link |
within the throat of muscles within the throat
link |
when the control of the tongue.
link |
I mean, what are these genes doing?
link |
You're pretty good.
link |
Yeah, you've made some very good guesses there
link |
So yes, one of the things that differ
link |
in the speech pathways of us
link |
and these song pathways of birds
link |
is some of the connections are fundamentally different
link |
than the surrounding circuits,
link |
like a direct cortical connection
link |
from the areas that control vocalizations in the cortex
link |
to the motor neurons that control the larynx in humans
link |
or the syrinx in birds.
link |
And so we've actually made a prediction
link |
that since some of these connections differ,
link |
we're gonna find genes that control neural connectivity
link |
and that specialize in that function, that differ.
link |
And that's exactly what we found.
link |
Genes that control what we call axon guidance
link |
and form-instant connections.
link |
And what was interesting,
link |
it was sort of in the opposite direction that we expected.
link |
That is, some of these genes,
link |
actually a number of them
link |
that control neural connectivity were turned off
link |
in the speech circuit.
link |
And it didn't make sense to us at first
link |
and so we started to realize the function of these genes
link |
are to repel connections from forming.
link |
So repulsive molecules.
link |
And so when you turn them off,
link |
they allow certain connections to form
link |
that normally would have not formed.
link |
So by turning it off,
link |
you gotta gain a function for speech.
link |
Other genes that surprised us
link |
were genes involved in calcium buffering, neural protection,
link |
like a parvalbumin or a heat shock protein.
link |
So when your brain gets hot, these proteins turn on.
link |
And we couldn't figure out for a long time
link |
why is that the case?
link |
And then the idea popped to me one day and said,
link |
ah, when I heard the larynx
link |
is the fastest firing muscles in the body, all right?
link |
In order to vibrate sound
link |
and modulate sound in the way we do,
link |
you have to control, you have to move those muscles,
link |
you know, three to four to five times faster
link |
than just regular walking or running.
link |
And so when you stick electrodes in the brain areas
link |
that control larynx vocalizations in these birds
link |
and I think in humans as well,
link |
those neurons are firing at a higher rate
link |
to control these muscles.
link |
And so what is that gonna do?
link |
You're gonna have lots of toxicity in those neurons
link |
unless you upregulate molecules
link |
that take out the extra load
link |
that is needed to control the larynx.
link |
And then finally, a third set of genes
link |
that are specialized in these speed circuit
link |
are involved in neuroplasticity.
link |
Neuroplasticity meaning allowing the brain circuits
link |
to be more flexible so you can learn better.
link |
I think learning how to produce speech
link |
is a more complex learning ability
link |
than say learning how to walk
link |
or learning how to do tricks and jumps and so forth
link |
Yeah, it's interesting as you say that
link |
because I realized that many aspects of speech
link |
are sort of reflexive.
link |
I'm not thinking about each word I'm gonna say.
link |
They just sort of roll out of my mouth.
link |
Hopefully with some forethought,
link |
we both know people that seem to think less,
link |
fewer synapses between their brain and their mouth
link |
than others, right?
link |
A lot of examples out there.
link |
And some people are very deliberate in their speech.
link |
But nonetheless, much of speech has to be precise
link |
and some of it less precise.
link |
In terms of plasticity of speech,
link |
and the ability to learn multiple languages,
link |
but even just one language,
link |
what's going on in the critical period,
link |
the so-called critical period?
link |
Why is it that, so my niece speaks Spanish,
link |
she's Guatemalan, speaks Spanish and English incredibly well.
link |
She's 14 years old.
link |
I've struggled with Spanish my whole life.
link |
My father's bilingual, my mother is not.
link |
I've tried to learn Spanish as an adult.
link |
It's really challenging.
link |
I'm told that had I learned it when I was eight,
link |
I would be better off.
link |
Or it would be installed within me.
link |
So the first question is,
link |
is it easier to learn multiple languages
link |
without an accent early in life?
link |
And then the second question is,
link |
if one can already speak more than one language
link |
as a consequence of childhood learning,
link |
is it easier to acquire new languages later on?
link |
So the answer to both of those questions is yes.
link |
In that, but to explain this,
link |
I need to let you know,
link |
actually the entire brain
link |
is undergoing a critical period development,
link |
not just the speech pathways.
link |
And so it's easier to learn how to play a piano.
link |
It's easier to learn how to ride a bike for the first time
link |
and so forth as a young child than it is later in life.
link |
What I mean easier in terms of when you start from,
link |
you start from first principles of learning something.
link |
So the very first time if you're gonna learn Chinese
link |
as a child versus the very first time
link |
you learn Chinese as an adult,
link |
or learning to play piano as a child versus an adult.
link |
But the speech pathways, or let's say speech behavior,
link |
I think has a stronger critical period change to it
link |
than other circuits.
link |
And what's going on there in general?
link |
Why do you need a critical period to make you more stable,
link |
to make you more stubborn, so to speak?
link |
The reason I believe is that the brain is not,
link |
brain can only hold so much information.
link |
And if you are undergoing rapid learning
link |
to acquire new knowledge,
link |
you also have to dump stuff,
link |
put memory or information in the trash, like in a computer.
link |
You only have so many gigabases of memory.
link |
And so therefore, plus also for survival,
link |
you don't wanna keep forgetting things.
link |
And so the brain is designed, I believe,
link |
to undergo this critical period and solidify the circuits
link |
with what you learned as a child
link |
and you use that for the rest of your life.
link |
And we humans stay even more plastic in our brain functions
link |
controlled by a gene called SR-GAP2.
link |
We have an extra copy of it
link |
that leaves our speech circuit in other brain regions
link |
in a more immature state throughout life
link |
compared to other animals.
link |
So we're more immature.
link |
We're still juvenile-like compared to other animals.
link |
But we still go through the critical periods
link |
And now the question you asked about
link |
if you learn more languages as a child,
link |
is it easier to learn as an adult?
link |
And that's a common finding out there in the literature.
link |
There are some that argue against it.
link |
But for those that support it, the idea there is
link |
that you are born with a set of innate sounds
link |
you can produce of phonemes and you narrow that down
link |
because not all languages use all of them.
link |
And so you narrow down the ones you use
link |
to string the phonemes together in the words that you learn
link |
and you maintain those phonemes as an adult.
link |
And here comes along another language
link |
that's using those phonemes in different combinations
link |
you're not used to.
link |
And therefore, it's like starting from first principles.
link |
But if you already have them
link |
in multiple languages that you're using,
link |
then it makes it easier to use them
link |
in another third or fourth language.
link |
So it's not like your brain has maintained greater plasticity
link |
is your brain has maintained greater ability
link |
to produce different sounds
link |
that then allows you to learn another language faster.
link |
Are the hand gestures associated with sounds
link |
or with meanings of words?
link |
I think the hand gestures are associated
link |
with both the sounds and the meaning.
link |
When I say sound, like if you are really angry, right?
link |
And you are making a loud screaming noise, right?
link |
You may make hand gestures
link |
that look like you're gonna beat the wall, right?
link |
Because you're making loud sounds and loud gestures,
link |
But if you wanna explain something like come over here,
link |
what I just do now to you, for those who can't see me,
link |
I swung my hand towards you and swung it here to me.
link |
That has a meaning to it, to come here.
link |
So just like with the voice,
link |
the hand gestures are producing both qualities of sounds.
link |
And for people that speak multiple languages,
link |
especially those that learn those multiple languages
link |
early in development,
link |
do they switch their patterns of motor movements
link |
according to, let's say, going from Italian to Arabic
link |
or from Arabic to French in a way that matches
link |
the precision of language that they're speaking?
link |
You just asked me a question I don't know the answer to.
link |
I would imagine that would make sense
link |
because of switching in terms of,
link |
sometimes people might call this code switching,
link |
even different dialects of the same language.
link |
Could you do that with your gestures?
link |
I imagine so, but I really don't know if that's true or not.
link |
I certainly don't know from my own experience
link |
because I only speak one language.
link |
Before we continue with today's discussion,
link |
I'd like to just briefly acknowledge our sponsor,
link |
Athletic Greens, now called AG1.
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Again, you can go to athleticgreens.com slash Huberman
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to claim that special offer.
link |
To go a little bit into the abstract, but not too far,
link |
what about modes of speech and language
link |
that seem to have a depth of emotionality and meaning,
link |
but for which it departs from structured language?
link |
Here's what I mean, poetry.
link |
I think of musicians, like there are some Bob Dylan songs
link |
that to me, I understand the individual words.
link |
I like to think there's an emotion associated with it.
link |
At least I experienced some sort of emotion
link |
and I have a guess about what he was experiencing.
link |
But if I were to just read it linearly without the music
link |
and without him singing it or somebody singing it like him,
link |
it wouldn't hold any meaning.
link |
So in other words, words that seem to have meaning
link |
but not associated with language,
link |
but somehow tap into an emotionality.
link |
So we call this difference semantic communication,
link |
communication with meaning, and affective communication,
link |
communication that has more of an emotional
link |
feeling content to it, but not with the semantics.
link |
And the two can be mixed up,
link |
like with singing words that have meaning
link |
but also have this affective emotional,
link |
you just love the sound of the singer that you're hearing.
link |
And initially, psychologists, scientists in general
link |
thought that these were gonna be controlled
link |
by different brain circuits.
link |
And it is the case there are emotional brain centers
link |
in the hypothalamus, in the cingulate cortex and so forth
link |
that do give tone to the sounds.
link |
But I believe based upon imaging work
link |
and work we see in birds,
link |
when birds are communicating semantic information
link |
in their sounds, which is not too often but it happens,
link |
versus affective communication,
link |
sing because I'm trying to attract the mate,
link |
my courtship song or defend my territory,
link |
it's the same brain circuits.
link |
It's the same speech-like or song circuits
link |
are being used in different ways.
link |
A friend of mine who's also a therapist said to me,
link |
it's possible to say, I love you with intense hatred
link |
and to say, I hate you with intense love.
link |
And reminded me that it's possible to hear
link |
both of those statements in either way.
link |
So I guess it's not just limited to song
link |
or poetry, it also, there's something about the intention
link |
and the emotional context in which something's spoken
link |
that it can heavily shape the way
link |
that we interpret what we hear.
link |
That's right, and I consider all of that actually meaning,
link |
even though I defined it as,
link |
as people commonly do semantic and affective communication,
link |
affective communication to say I hate you
link |
but love, right, does have emotional meaning to it.
link |
And so one's more like an object kind of meaning
link |
or an abstract kind of meaning.
link |
There's several other points here I think it's important
link |
for those listening out there to hear,
link |
is that when I say also this affective
link |
and semantic communication being used
link |
by similar brain circuits,
link |
it also matters the side of the brain.
link |
In birds and in humans, there's left right dominance
link |
for learned communication, learned sound communication.
link |
So the left in us humans is more dominant for speech.
link |
But the right has a more balance for singing
link |
or processing musical sounds
link |
as opposed to processing speech.
link |
Both get used for both reasons.
link |
And so when people say your right brain
link |
is your artistic brain and your left brain
link |
is your thinking brain, this is what they're referring to.
link |
And so that's another distinction.
link |
The second thing that's useful to know
link |
is that all vocal learning species use their learned sounds
link |
for this emotional affective kind of communication.
link |
But only a few of them like humans
link |
and some parrots and dolphins use it
link |
for the semantic kind of communication calling speech.
link |
And that has led a number of people to hypothesize
link |
that the evolution of spoken language of speech
link |
evolved first for singing,
link |
for this more like emotional kind of made attraction
link |
like the Jennifer Lopez, the Ricky Martin kind of songs
link |
And then later on, it became used for abstract communication
link |
like we're doing now.
link |
Well, that's a perfect segue for me
link |
to be able to ask you about your background
link |
and motor control, not only of the hands, but of the body.
link |
So you have a number of important distinctions to your name,
link |
but one of them is that you were a member
link |
of the Alvin Ailey Dance School of Dance.
link |
So you're an accomplished and quite able dancer, right?
link |
Tell us a little bit about your background
link |
in the world of dance.
link |
And how it informs your interest in neuroscience,
link |
excuse me, and perhaps even how it relates specifically
link |
to your work on speech and language.
link |
Well, it's interesting.
link |
And then this kind of history even goes before my time.
link |
So in my family, my mother and father's side,
link |
they both went to the High School of Music and Art
link |
here in New York City.
link |
And particularly my mother's family,
link |
going back multiple generations, they were singers.
link |
And I even did my family genealogy and found out
link |
not only we have some relationships
link |
to some well-known singers,
link |
distant relationships like Thelonious Monk,
link |
but going back to the plantations in North Carolina
link |
and so forth, my ancestors were singers in the church
link |
for the towns and so forth.
link |
And this somehow got passed on multiple generations
link |
And I thought I was gonna grow up
link |
and be a famous singer, right?
link |
And me and my brothers and sister formed a band
link |
when we were kids and so forth.
link |
And, but it turned out that I didn't inherit
link |
the singing talents of some of my other family members,
link |
even though it was okay, but not like my brother
link |
or not like my mother or my aunts and my cousin Pudafe,
link |
who's now a talented Native American singer.
link |
And so that then influenced me to do other things.
link |
And I started competing in dance contests.
link |
Actually this is around the time of the Saturday Night Fever
link |
and I was as a teenager and I started winning dance contests
link |
and I thought, oh, I can dance.
link |
And I auditioned for the High School of Performing Arts
link |
and I got in here in New York City
link |
and got into ballet dance and got in, right?
link |
And thought if I learn ballet, I can learn everything else.
link |
It was that idea, if you learn something classical,
link |
it can teach you very little.
link |
If you learn something classical, it can teach you
link |
for everything else.
link |
And I was, yeah, at Alvin Ailey Dance School,
link |
Joffrey Ballet Dance School.
link |
And at the end of my senior concert,
link |
I had this opportunity to audition
link |
for the Alvin Ailey Dance Company
link |
and I had an opportunity to go to college.
link |
And I also fell in love with another passion
link |
that my father had, which was science.
link |
And so I liked science in high school
link |
and I found an overlap also between the arts
link |
Both required creativity, hard work, discipline,
link |
new discovery, both weren't boring to me.
link |
And the one decision I made at that senior dance concert
link |
was talking to the Alvin Ailey recruiter
link |
and thinking about it, I have to make a decision.
link |
And I thought something my mother taught me,
link |
because she was growing up in the 1960s cultural revolution,
link |
do something that has a positive impact on society.
link |
I thought I can do that better as a dancer
link |
So now jump, I get into college, undergraduate school,
link |
I major in molecular biology and mathematics.
link |
I decided I wanted to be a biologist,
link |
got into graduate school, wanted to study the brain
link |
at the Rockefeller University.
link |
So I went from Hunter College to Rockefeller University.
link |
And so now I got to the brain
link |
and why did I choose the brain
link |
is because it controls dancing.
link |
But there wasn't anybody studying dancing.
link |
I wanted to study the brain,
link |
something that's really interesting and complex.
link |
And I thought, ah, language is what it does.
link |
You couldn't study that in mice,
link |
you couldn't study in non-human primates,
link |
but these birds do this wonderful thing
link |
that Fernando Nadebaum was studying at Rockefeller.
link |
And so that's what got me into the birds.
link |
And then jumping now 15 years later,
link |
yeah, that's right, even after I'm into
link |
now having my own lab studying vocal learning
link |
in these birds as a model for language in humans,
link |
it turns out that Ani Patel and others
link |
have discovered that only vocal learning species
link |
can learn how to dance.
link |
That's right, yes.
link |
So I've seen these, I'm just scrolling through
link |
the files here in my mind.
link |
I think about every once in a while someone will,
link |
Every once in a while someone will send me
link |
one of these little Instagram or Twitter videos
link |
of a parrot doing what looks to me like dance.
link |
Typically it's a cockatoo.
link |
That's right, that's right.
link |
Even foot stomping to the sound.
link |
Famous one called snowball out there,
link |
but there are many snowballs out there.
link |
They're all, all the dancing birds are named snowball.
link |
That's interesting tactic.
link |
So only animals with language dance.
link |
Yeah, vocal learning in particular,
link |
the ability to imitate sounds, yes.
link |
Yes, and this now is bringing my life full circle.
link |
All right, and I, and so when that was discovered in 2009,
link |
at that same time in my lab at Duke we discovered
link |
that vocal learning brain pathways in songbirds
link |
as well as in humans and in parrots, right,
link |
like snowball, are embedded within circuits
link |
that control learning how to move.
link |
And that led us to a theory we called
link |
the brain pathway or motor theory of vocal learning origin,
link |
where the brain pathways for vocal learning and speech
link |
evolve by a whole duplication
link |
of the surrounding motor circuits
link |
involving learning how to move.
link |
Now, how does that explain dance, right?
link |
Well, when snowball, the cockatoos are dancing,
link |
they're using the brain regions
link |
around their speech-like circuits
link |
to do this dancing behavior.
link |
And so what's going on there?
link |
What we hypothesized and now like to test
link |
is that when speech evolved in humans
link |
and the equivalent behavior in parrots and songbirds,
link |
it required a very tight integration
link |
in the brain regions that can hear sound
link |
with the brain regions that control your muscles
link |
from moving your larynx and tongue and so forth
link |
for producing sound.
link |
And that tight auditory motor integration,
link |
we argued then contaminated the surrounding brain regions.
link |
And that contamination of the surrounding brain regions
link |
now allows us humans in particular in parrots
link |
to coordinate our muscle movements
link |
of the rest of the body with sound
link |
in the same way we do for speech sounds.
link |
Well, so we're speaking with our bodies when we dance.
link |
And I have to say that as poor as I am
link |
at speaking multiple languages,
link |
I'm even worse at dancing, so.
link |
But I guarantee you're better than a monkey.
link |
But not Snowball the Cockatoo.
link |
Maybe not Snowball.
link |
On YouTube, we have a video
link |
where there's some scientists dancing with Snowball
link |
and you'll see Snowball's doing better
link |
than some of the scientists.
link |
Okay, well, as long as I'm not the worst
link |
of all scientists at dancing,
link |
there's always neuroplasticity.
link |
May it save me someday.
link |
You said something incredible that I completely believe,
link |
even though I have minimum to,
link |
let's just say minimum dancing ability.
link |
I can get by at a party or wedding
link |
without complete embarrassment,
link |
but I don't have any structured training.
link |
So the body clearly can communicate with movement.
link |
As a trained dancer and knowing other trained dancers,
link |
I always think of dance and bodily movement
link |
and communication through bodily movement
link |
as a form of a wordlessness,
link |
like a state of wordlessness.
link |
In fact, the few times when I think
link |
that maybe I'm actually dancing modestly well
link |
for the context that I'm in,
link |
where I see other people dancing
link |
and they seem to just be very much in the movement,
link |
it's almost like a state of non-language,
link |
non-spoken language.
link |
And yet what you're telling me
link |
is that there's a direct bridge at some level
link |
between the movement of the body and language.
link |
So is there a language of the body
link |
that is distinct from the language of speech?
link |
And if so, or if not, how do those map onto one another?
link |
What does that Venn diagram look like?
link |
Yeah, yeah, so let me define first dance
link |
in this context of vocal learning species.
link |
This is the kind of dancing
link |
that we are specialized in doing,
link |
and the vocal learning species is specialized in doing,
link |
is synchronizing body movements of muscles
link |
to the rhythmic beat of music.
link |
And for some reason, we like doing that.
link |
We like synchronizing to sound
link |
and doing it together as a group of people.
link |
And that kind of communication amongst ourselves
link |
is more like the effective kind of communication
link |
I mentioned earlier, unlike the semantic kind.
link |
So we humans are using our voices
link |
more for the semantic abstract communication,
link |
but we're using learned dance
link |
for the effective emotional bonding kind of communication.
link |
It doesn't mean we can't communicate
link |
semantic information in dance, and we do it,
link |
but it's not as popular.
link |
Like a ballet in the Nutcracker,
link |
it is popular where they are communicating,
link |
the Arabian guy comes out,
link |
which I was the Arabian guy in the ballet Nutcracker,
link |
that's how I remember,
link |
for the Westchester Ballet Company when I was a teenager.
link |
We're trying to communicate meaning in our ballet dance
link |
and it can go on with a whole story and so forth.
link |
But people don't interpret that as clearly as speech.
link |
They're seeing the ballet with semantic communication
link |
with a lot of emotional content.
link |
Whereas you go out to a club,
link |
you're not communicating, okay, how are you feeling today?
link |
Tell me about your day and so forth.
link |
You're trying to synchronize with other people
link |
in an effective way.
link |
And I think that's because the dance brain circuit
link |
inherited the more ancient part of the speech circuit,
link |
which was for singing.
link |
I always had the feeling that with certain forms of music,
link |
in particular opera, but any kind of music
link |
where there are some long notes sung,
link |
that at some level there was a literal resonance
link |
created between the singer and the listener.
link |
That, or I think of like the deep voice of a Johnny Cash
link |
or where at some level you can almost feel the voice
link |
And in theory, that could be the vibration of the,
link |
or the firing of the phrenic nerve
link |
controlling the diaphragm for all I know.
link |
Is there any evidence that there's a coordination
link |
between performer and audience
link |
at the level of mind and body?
link |
I'm gonna say possibly yes.
link |
And the reason why is because I just came back
link |
from a conference on the neurobiology of dance.
link |
Clearly I'm going to the wrong meetings.
link |
Vision science can be so boring.
link |
Well, one of my colleagues, Tecumseh Fitch
link |
and Jonathan Fritz, they organized a particular section
link |
on this conference in Virginia.
link |
And this is the first time I was in the room
link |
with so many neuroscientists
link |
studying the neurobiology of dance.
link |
It's a new field now in the last five years.
link |
And there was one lab where they were putting EEG electrodes
link |
on the dancers, on two different dancers
link |
partnering with each other,
link |
as well as the audience seeing the dance.
link |
And some argued, okay,
link |
if you're listening to the music as well,
link |
how are you responding?
link |
Because you're asking a question about music
link |
and I'm giving you an answer about dance.
link |
And what they found is that the dancers,
link |
when they resonated with each other during the dance
link |
or the audience listening to the dancers and the music,
link |
there's some resonance going on there
link |
that they score as higher resonance.
link |
Their brain activity with these wireless EEG signals
link |
are showing something different.
link |
And so that's why I say possible yet.
link |
It needs more rigorous study.
link |
And this is some stuff they publish,
link |
but it's not prime time yet,
link |
but they're trying to figure this out.
link |
So at least if I can't dance well,
link |
maybe I can hear and feel what it is
link |
to dance in a certain way.
link |
And this will be, some people will think that they,
link |
even songs that they hear
link |
and they can almost sing to themselves in their own head
link |
and they know what they want it to sound like.
link |
And you know what it really sounds good,
link |
what it sounds like,
link |
but they can't get their voice to do it.
link |
I'm raising, for those listening, I'm raising my hand.
link |
No musical ability.
link |
Others in my household have tremendous musical ability
link |
with instruments and with voice, but not me.
link |
And so this is one of my selfish goals
link |
of trying to find the genetics
link |
of why can some people sing really well and some not?
link |
Is there some genetic predisposition to that?
link |
And then can I modify my own muscles
link |
or brain circuits to sing better?
link |
You're still after the sing.
link |
I guess this is what happens
link |
when siblings vary in proficiency
link |
is that that competitiveness
link |
amongst brothers and sisters never goes away.
link |
I've been trying to breathe
link |
as good as my brother, Mark and Victor,
link |
for the rest of my entire life.
link |
Watch out, Mark and Victor.
link |
He's coming for you with neuroscience
link |
Earlier, you said that you discovered that you could dance.
link |
That caught my ear.
link |
It sounds like you didn't actually have to,
link |
I'm not suggesting you didn't work hard at it,
link |
but that at the moment where you discovered it,
link |
it just sort of was a skill that you had
link |
that up until that point,
link |
you didn't target a life in the world of dance.
link |
But the fact that you, quote unquote,
link |
discovered that you could dance really well
link |
and then went to this incredible school of dance
link |
and did well tells me that perhaps there is an ability
link |
that was built up in childhood
link |
and or that perhaps we do all have
link |
different genetic leanings for different motor functions.
link |
Well, for me, both explanations could be possible.
link |
For the first, I grew up in a family
link |
listening to Motown songs,
link |
dancing at parties and so forth, family parties,
link |
an African-American family, basically.
link |
And so I grew up dancing from a young child,
link |
but this discovery, you know,
link |
maybe dancing even more so in terms of a talent,
link |
the genetic component, if it really exists, I don't know.
link |
You know, with my 23andMe results,
link |
it says I have the genetic substitutions
link |
that are associated with high-intensity athletes
link |
and fast-twitch muscles.
link |
Maybe that could have something to do with me
link |
being able to synchronize my body to rhythmic sounds.
link |
Maybe, maybe better than some others.
link |
It turns out that my genetics also show
link |
that I have a genetic substitute
link |
that makes it hard for me to sing on pitch.
link |
And so that does correlate with my, you know,
link |
even though I can sing on this pitch,
link |
especially if I hear a piano or, you know, kind of playing it
link |
but, you know, maybe that's why my siblings, you know,
link |
who didn't have that genetic predisposition
link |
in his 23andMe results, you know,
link |
could go along with the genetic component as well.
link |
I'm imagining family gatherings with 23andMe data
link |
and intense arguments about it.
link |
Innate and learned ability, fun.
link |
Love to be an attendant.
link |
I'm not inviting myself to your Thanksgiving dinner,
link |
by the way, but I suppose I am.
link |
You're welcome to.
link |
I'll bring my 23andMe data.
link |
I'd love to chat a moment about facial expression
link |
because that's a form of motor pattern that, you know,
link |
I think for most people out there,
link |
just think about smiling and frowning,
link |
but there are of course, you know, thousands,
link |
if not millions of micro expressions and things of that sort,
link |
many of which are subconscious.
link |
And we're all familiar with the fact
link |
that when what somebody says
link |
doesn't match some specific feature
link |
of their facial expression, that it can call, you know,
link |
that mismatch can cue our attention,
link |
especially among people that know each other very well.
link |
Like somebody will say, well, you said that,
link |
but your right eye twitched to the, you know,
link |
a little bit in a way that tells me
link |
that you didn't really mean that, these kinds of things.
link |
Or in the opposite example,
link |
when the emotionality and the content of our speech
link |
is matched to a facial expression,
link |
there's something that's just so wonderful about that
link |
because it seems like everything's aligned.
link |
So how does the motor circuitry
link |
that controls facial expression
link |
map onto the brain circuits that control language, speech,
link |
and even bodily and hand movements?
link |
You ask a great question
link |
because we both know some colleagues like Winrich Freiwald
link |
at Rockefeller University,
link |
who study facial expression and the neurobiology behind it.
link |
And now we both share some students that were co-mentoring
link |
and talk about this same question that you brought up.
link |
And what I'm learning a lot is that non-human primates
link |
have a lot of diversity in their facial expression
link |
like we humans do.
link |
And what we know about the neurobiology
link |
of brain regions controlling those muscles of the face
link |
is that these non-human primates and some other species
link |
that don't learn how to imitate vocalizations,
link |
they have strong connections from the cortical regions
link |
to the motor neurons that control facial expressions,
link |
but absent connections or weak connections
link |
to the motor neurons that control the voice.
link |
So I think our diverse facial expression,
link |
even though it's more diverse than these non-human primates,
link |
there was already a pre-existing diversity of communication,
link |
whether it's intentional or unconscious
link |
through facial expression in our ancestors.
link |
And on top of that, we humans now add the voice
link |
along with those facial expressions.
link |
And in terms of language learning when we're kids,
link |
I mean, children fortunately are not told
link |
to fake their expressions or to smile
link |
when they say I'm happy.
link |
So at some point, everybody learns for better or for worse
link |
how to untangle these different components
link |
of hand movement, body posture,
link |
speech, and facial expression.
link |
But in their best form, I would say,
link |
assuming that the best form is always,
link |
I guess there are instances where, for safety reasons,
link |
one might need to feign some of these aspects of language.
link |
But in most cases, when those are aligned,
link |
it seems like that could reflect
link |
that all the different circuitries
link |
are operating in parallel,
link |
but that the ability to misalign these
link |
is also a powerful aspect to our maturation.
link |
I even think of theater, for instance,
link |
where deliberate disentangling of these areas is important,
link |
but also we know when an actor, when it feels real,
link |
and when it looks like, when bad acting is oftentimes
link |
when the facial expression or body posture
link |
just doesn't quite match what we're hearing.
link |
So are these skills that people that learn and acquire
link |
according to adaptability and profession,
link |
or do you think that all children
link |
and all adults eventually learn
link |
how to couple and uncouple these circuits a little bit?
link |
Yeah, I think it's this similar argument
link |
I mentioned earlier about the innate
link |
and the learned for the vocalizations.
link |
And by the way, when I say we humans have facial expressions
link |
associated with our vocalizations
link |
in a different way than primates, non-human primates,
link |
it's the learned vocalizations I'm talking about.
link |
So there is a common view out there
link |
that facial expressions in non-human species,
link |
like non-human primates, or you can have them in birds too,
link |
are innate, all right?
link |
And so they're reflexive controlled.
link |
I don't believe that.
link |
I think there's some learned component to it,
link |
and I think we have more learning component to it as well,
link |
but we also have an innate component.
link |
And so if you try to put your hands behind your back
link |
and hold your fists, or even just not,
link |
and try to speak and try to communicate,
link |
it's actually harder to do.
link |
You have to force yourself or put it by your side.
link |
This comes naturally.
link |
Facial expressions comes naturally
link |
because there is an innate component.
link |
And yes, you have to learn how to dissociate the two,
link |
communicate something angry with your hands
link |
or with your face, but politely with your voice.
link |
It's very hard to separate at those two
link |
because there is that innate component
link |
that brings them together.
link |
So it's like an email too.
link |
You're emailing and someone says something by email.
link |
Someone can interpret that angrily or gently,
link |
and it becomes ambiguous.
link |
The facial expressions get rid of that ambiguity.
link |
I'm so glad you brought that out
link |
because my next question was and is about written language.
link |
The first question I'll ask is when you write,
link |
either type or write things out by hand,
link |
do you hear the content of what you want to write
link |
in your head, just you personally?
link |
Yeah, and I know that I do
link |
because I was trying to figure out a debate about this issue
link |
and trying to resolve the debate
link |
with my own self-experimentation on me.
link |
I ask that because a quite well-known colleague of ours,
link |
Carl Deisseroth at Stanford,
link |
who's been on this podcast and is of optogenetics fame
link |
and psychiatry fame, et cetera.
link |
Yeah, he sends his regards.
link |
And told me that his practice for writing
link |
and for thinking involves a quite painful process
link |
of forcing himself to sit completely still
link |
and think in complete sentences,
link |
to force thinking in complete sentences.
link |
And when he told me that, I decided to try this exercise
link |
and it's quite difficult.
link |
First of all, it's difficult for the reason
link |
that you mentioned, which is that with many thoughts,
link |
I want to look around
link |
and I start to gesticulate with my hands.
link |
So there it is again,
link |
the connection between language and hand movement,
link |
even if one isn't speaking.
link |
And the other part that's challenging
link |
is I realized that while we write in complete sentences,
link |
most of the time, we'll talk about how that's changing now
link |
and texting, et cetera,
link |
that we don't often think in complete sentences
link |
and specifically in simple declarative sentences,
link |
that a lot of our thoughts would be,
link |
if they were written out onto a page,
link |
would look pretty much like passive language
link |
that a good copy editor or a good editor would say,
link |
oh, like we need to cross this out,
link |
make this simple and declarative.
link |
So what I'm getting at here is what is the process
link |
of going from a thought to language to written word?
link |
And I also wanted to touch on handwritten versus typed,
link |
but thought to language to written word,
link |
what's going on there?
link |
What do we know about the neural circuitry?
link |
And I was gonna ask, why is it so hard?
link |
But now I want to ask, why is this even possible?
link |
It seems like a very challenging
link |
neural computational problem.
link |
And coming from the linguistic world
link |
and even just the regular neurobiology world,
link |
going back to something I said before
link |
is about a separate language module in the brain.
link |
There was this thought or hypothesis
link |
that this language module
link |
has all these complex algorithms to them,
link |
and they're signaling to the speech circuit,
link |
how to produce the sounds,
link |
the hand circuit, how to write them or gesture,
link |
the visual pathway on how to interpret them from reading,
link |
and the auditory pathway for listening.
link |
I don't think that's the case, all right?
link |
And that this thinking
link |
where there's this internal speech going on,
link |
what I think is going on
link |
is to explain what you're asking is about,
link |
that I'm gonna take it from the perspective
link |
of reading something.
link |
You read something on a paper,
link |
the signal from the paper goes through your eyes,
link |
it goes to the back of your brain
link |
to your visual cortical regions eventually,
link |
and then you now got to interpret that signal
link |
in your visual pathway of what you're reading.
link |
How are you gonna do that in terms of speech?
link |
That visual signal then goes to your speech pathway
link |
in the motor cortex in front here in Broca's area,
link |
and you silently speak what you read in your brain
link |
without moving your muscles.
link |
And sometimes, actually, if you put electrodes,
link |
EMG electrodes on your laryngeal muscles,
link |
even on birds, you can do this,
link |
you'll see activity there while reading
link |
or trying to speak silently,
link |
even though no sound's coming out.
link |
And so your speech pathway is now speaking
link |
what you're reading.
link |
Now, to finish it off,
link |
that signal is sent to your auditory pathway
link |
so you can hear what you're speaking in your own head.
link |
That's incredible.
link |
And this is why it's complicated,
link |
because you're using like three different pathways,
link |
the visual, the speaking motor one,
link |
and the auditory to read.
link |
Oh, and then you gotta write, right?
link |
Okay, here comes the fourth one.
link |
Now the hand area's next to your speech pathway
link |
has gotta take that auditory signal
link |
or even the adjacent motor signals for speaking
link |
and translate it into a visual signal on paper.
link |
So you're using at least four brain circuits,
link |
which includes the speech production
link |
and the speech perception pathways to write.
link |
And finally explains to me why,
link |
so I was weaned teaching undergraduates,
link |
graduate students, and medical students.
link |
And I've observed that when I'm teaching,
link |
I have to stop speaking
link |
if I'm going to write something on the board.
link |
I just have to stop all speaking completely.
link |
It turns out this is an advantage to catch
link |
because it allows me to catch my voice.
link |
It allows me to slow down a bit,
link |
breathe and inhale some oxygen and so on,
link |
because I tend to speak quickly
link |
if I'm not writing something out.
link |
So there's a break in the circuitry for me,
link |
or at least they are distinct enough
link |
that I have to stop and then write something.
link |
Yes, that does imply competing brain circuits
link |
for your conscious attention.
link |
We have colleagues up at Columbia Med
link |
who are known at least in our circles
link |
for voice dictating their papers,
link |
not writing them out,
link |
but just speaking into a voice recorder.
link |
I've written papers that way.
link |
It doesn't feel quite as natural for me
link |
as writing things out,
link |
but not because I can go quickly
link |
from thought to language to typing.
link |
I type reasonably fast.
link |
I can touch type now.
link |
I don't think I ever taught my,
link |
I think I taught myself.
link |
I never took a touch typing course,
link |
but it just sort of happened now.
link |
My motor system seems to know where the keys are
link |
with enough accuracy that it works.
link |
This is remarkable to me that any of us can do this,
link |
but when it comes to writing,
link |
what I've found is that if my rate of thought
link |
and my rate of writing are aligned nicely,
link |
However, if I'm thinking much faster than I can write,
link |
And certainly if I'm thinking more slowly
link |
than I want to write,
link |
that's also a problem.
link |
And the solution for me has been to write with a pen.
link |
I'm in love with these,
link |
and I have no relationship to the company,
link |
although if they want to work with us,
link |
I love these Pilot V5, V7s,
link |
because not necessarily because of the ink or the feel,
link |
although I like that as well,
link |
but because of the rate that it allows me to write.
link |
They write very well slowly
link |
and they write very well quickly.
link |
And so I have this theory supported only
link |
by my own ANIC data, no peer-reviewed study,
link |
that writing by hand is fundamentally different
link |
than typing out information.
link |
Is there any evidence that this motor pathway for writing
link |
is better or somehow different
link |
than the motor pathway for typing?
link |
Yeah, that's interesting.
link |
And I don't know of any studies,
link |
I have my own personal experience as well,
link |
but trying to put this into the context,
link |
if I had to design an experiment
link |
to test the hypothesis here,
link |
to explain your experience in mind,
link |
is that writing by hand, I would argue,
link |
requires a different set of less skills with the fingers
link |
So you have to coordinate your fingers
link |
more in opposite directions and so forth with typing,
link |
but also writing by hand requires more arm movement.
link |
And so therefore, I would argue that the difficulty there
link |
could be in the types of muscles
link |
and the fine motor control you need of those muscles
link |
along with speaking in your brain at the same time.
link |
So basically I'm coarse, I'm a brute,
link |
and so it makes sense that a more primitive writing device
link |
That's right, yes.
link |
But let me add to this in terms of the,
link |
in my own personal experience, right,
link |
what I find is I can write something faster by hand
link |
for a short period of time compared to typing.
link |
And that is because I think I run out of the energy
link |
in my arm movements faster than I run out of muscle energy
link |
in my finger movements.
link |
And I think it takes a longer time for us to write words
link |
with our fingers because, and in terms of the speech.
link |
So I think you're writing, whether it's by hand or typing,
link |
and your speech, it only will align very well
link |
if you can type as fast as you can speak
link |
or write as fast as you can speak in your head.
link |
So what you've done, if I understand correctly,
link |
is created a bridge between thought and writing,
link |
and that bridge is speech.
link |
That bridge is speech, that's right, that's right.
link |
When you're writing something out,
link |
you're speaking it to yourself.
link |
And if you're speaking faster than you can type,
link |
you got a problem.
link |
I do a number of podcast episodes
link |
that are not with guests, but solo episodes.
link |
And as listeners know, these are very long episodes,
link |
often two or more hours.
link |
And we joke around the podcast studio
link |
that I will get locked into a mode of speech
link |
where some of it is more elaborative and anecdotal,
link |
and then I'll punch out simple declarative sentences.
link |
I find it very hard to switch from one module to the next.
link |
The thing that I have done
link |
in order to make that transition more fluid
link |
and prep for those podcast episodes
link |
is actually to read the lyrics of songs
link |
and to sing them in my head
link |
as a way of warming up my vocal cords.
link |
But luckily for those around me,
link |
when I do that, I'm not actually singing out loud.
link |
And so what you're telling me supports this idea
link |
that even when we are imagining singing
link |
or writing in our mind, we are exercising our vocal cords.
link |
You're actually getting little low potentials
link |
of electrical currents reaching your muscles there,
link |
which also means you're exercising
link |
your speech brain circuits too,
link |
without actually going with the flow of activity
link |
And this idea of singing helps you as well.
link |
Even with Parkinson's patients and so forth,
link |
when they want to say something,
link |
singing or listening to music helps them move better.
link |
And the idea there is that the brain circuits for singing,
link |
or let's say the function of the brain circuits for speech
link |
being used for singing first is the more ancestral trait.
link |
And that's why it's easier to do things with singing
link |
sometimes than it is with speaking.
link |
Stutter is a particularly interesting case
link |
and one that every once in a while,
link |
I'll get questions about this from our audience.
link |
Stutter is complicated in a number of ways,
link |
but culturally, in my understanding from these emails
link |
that I receive is that stutter can often cause people
link |
to hide and speak less because it can be embarrassing.
link |
And we are often not patient with stutter.
link |
We also have the assumption that if somebody's stuttering,
link |
that their thinking is slow,
link |
but it turns out there are many examples historically
link |
of people who could not speak well,
link |
but who were brilliant thinkers.
link |
I don't know how well they could write,
link |
but they found other modes of communication.
link |
I realize that you're not a speech pathologist
link |
or therapist, but what is the current neurobiological
link |
understanding of stutter and what's being developed
link |
in terms of treatments for stutter?
link |
Yeah, so we actually accidentally came across
link |
stuttering in songbirds
link |
and we've published several papers on this.
link |
So try to figure out the neurobiological basis.
link |
The first study we had was a brain area
link |
called the basal ganglia or the striatum part
link |
of the basal ganglia involved in coordinating movements,
link |
learning how to make movements.
link |
When it was damaged in a speech-like pathway in these birds,
link |
what we found is that they started to stutter
link |
as the brain region recovered.
link |
And unlike humans, they actually recovered
link |
after three or four months.
link |
And why is that the case?
link |
Because bird brains undergoes new neurogenesis
link |
in a way that human or mammal brains don't.
link |
And it was the new neurons that were coming in
link |
into the circuit, but not quite
link |
with the right proper activity was resulting
link |
in this stuttering in these birds.
link |
And after it was repaired, not exactly the old song
link |
came back after the repair,
link |
but still it recovered a lot better.
link |
And it's now known, they call this neurogenics stuttering
link |
in humans, damage to the basal ganglia
link |
or some type of disruption to the basal ganglia
link |
at a young age also causes stuttering in humans.
link |
And even those who are born with stuttering,
link |
it's often the basal ganglia that's disrupted
link |
in some other brain circuit.
link |
And we think the speech part of the basal ganglia.
link |
Can adults who maintain a stutter from childhood
link |
repair that stutter?
link |
They can repair it with a therapy,
link |
with learning how to speak slower,
link |
learning how to tap out a rhythm during such.
link |
And yeah, I'm not a speech pathologist,
link |
but I started reading this literature
link |
and talking to others that, you know,
link |
colleagues who actually study stuttering.
link |
So yes, there are ways to overcome the stuttering
link |
through behavioral therapy.
link |
And I think all of the tools out there
link |
have something to do with sensory motor integration.
link |
Controlling what you hear with what you output
link |
in a thoughtful controlled way helps reduce the stuttering.
link |
There are a couple examples from real life
link |
that I want to touch on.
link |
And one is somewhat facetious,
link |
but now I realize is a serious neurobiological issue.
link |
Serious meaning, I think, interesting,
link |
which is that every once in a while
link |
I will have a conversation with somebody
link |
who says the last word of the sentence along with me.
link |
And it seems annoying in some instances,
link |
but I'm guessing this is just a breakthrough
link |
of the motor pattern
link |
that they're hearing what I'm saying very well.
link |
So I'm going to interpret this kindly
link |
and think they're hearing what I'm saying.
link |
They're literally hearing it in their mind
link |
and they're getting that low level electrical activity
link |
And they're just joining me in the enunciation
link |
of what I'm saying, probably without realizing it.
link |
Can we assume that that might be the case?
link |
Well, I wouldn't be surprised.
link |
So the motor theory of speech perception
link |
where this idea originally came,
link |
what you hear is going through your speech circuit
link |
and then also activating those muscles slightly.
link |
So yes, so one might argue,
link |
okay, is that speech circuit now interpreting
link |
what that person is speaking now you listening to me
link |
and is going to finish it off
link |
because it's already going through their brain
link |
and they can predict it.
link |
That would be one theory.
link |
I don't think the verdict out there is no, but that's one.
link |
The other is synchronizing turn-taking in the conversation
link |
where you're acknowledging that we understand each other
link |
by finishing off what I say.
link |
And it's almost like a social bonding kind of thing.
link |
The other could be, I want the person to shut out
link |
so I can speak as well and take that turn.
link |
And each pair of people have a rhythm to their conversation.
link |
And if you have somebody who's overtalkative
link |
versus undertalkative or vice versa,
link |
that rhythm can be lost in them finishing off
link |
and going back and forth.
link |
But I think having something to do with turn-taking as well
link |
makes a lot of sense.
link |
I have a colleague at Stanford who says
link |
that interruption is a sign of interest.
link |
I'm not sure that everyone agrees.
link |
I think it's highly contextual,
link |
but there is this form of a verbal nod
link |
of saying, or things of that sort.
link |
And there are many of these,
link |
and I'm often told by my audience
link |
that I'd interrupt my guests and things of that sort.
link |
Oftentimes I'll just get caught in the natural flow
link |
of the conversation.
link |
Well, I think we've had pretty good turn-taking here,
link |
That's so far, so good.
link |
I'm glad you feel that way,
link |
because especially in the context of a discussion
link |
about language, this seems important.
link |
Texting is a very, very interesting evolution of language,
link |
because what you've told us is that we have a thought,
link |
it's translated into one word,
link |
translated into language.
link |
It might not be complete sentences, but texting,
link |
I have to imagine this is the first time
link |
in human evolution where we've written with our thumbs.
link |
So I don't know, it seems more primitive to me
link |
than typing with fingers around your hands,
link |
but hey, who am I to judge the evolution of our species
link |
in one direction or the other?
link |
But the shorthand, often grammatically deficient,
link |
incomplete sentence form of texting
link |
is an incredible thing to see.
link |
Early in relationships, romantic relationships,
link |
people will often evaluate the other's text
link |
and their ability to use proper grammar
link |
and spelling, et cetera.
link |
This often quickly degrades,
link |
and there's an acceptance
link |
that we're just trying to communicate through shorthand.
link |
Almost military-like shorthand,
link |
but with internally consistent between people,
link |
but there's no general consensus of what things mean.
link |
But WTFs and OMGs and all sorts of things.
link |
I wonder sometimes whether or not
link |
we are getting less proficient at speech
link |
because we are not required
link |
to write and think in complete sentences.
link |
I'm not being judgmental here.
link |
I see this in my colleagues.
link |
I see this in myself.
link |
This is not a judgment of the younger generation.
link |
I also know that slang has existed for decades,
link |
if not hundreds of years,
link |
but I also know that I don't speak the same way
link |
that I did when I was a teenager
link |
because I've suppressed a lot of that slang,
link |
not because it's inappropriate or offensive,
link |
although some of it was, frankly,
link |
but because it's out of context.
link |
So what do you think is happening to language?
link |
Are we getting better at speaking, worse at speaking?
link |
And what do you think the role of things like texting
link |
and tweeting and shorthand communication, hashtagging,
link |
what's that doing to the way that our brains work?
link |
Yeah, I think that one, in terms of
link |
measuring your level of sophistication and intelligence,
link |
and you say OMG, right?
link |
I think that also could be a cultural thing
link |
that, ah, you belong to the next generation.
link |
Or you're being cool.
link |
If you're an older person using OMG and other things
link |
that the younger generation would use.
link |
But if I really think about it clearly,
link |
texting actually has allowed
link |
for more rapid communication amongst people.
link |
I think without the invention of the phone before then,
link |
or texting back and forth,
link |
you had to wait days for a letter to show up.
link |
You couldn't call somebody on the phone and talk as well,
link |
you know, and so this rapid communication,
link |
but in terms of the rapid communication
link |
of writing in this case.
link |
So I think actually, it's more like a use it or lose it
link |
kind of a thing with the brain.
link |
The more you use a particular brain region or circuit,
link |
the more enhanced, it's like a muscle.
link |
The more you exercise it, the more healthier it is,
link |
the bigger it becomes and the more space it takes
link |
and the more you lose something else.
link |
So I think texting is not
link |
decreasing the speech prowess
link |
or the intellectual prowess of speech.
link |
It's converting it and using it a lot in a different way.
link |
In a way that may not be as rich in regular writing
link |
because you can only communicate so much nuance
link |
in short term writing.
link |
But whatever is being done,
link |
you got people texting hours and hours and hours
link |
So whatever your thumb circuit
link |
is gonna get pretty big actually.
link |
I do wonder whether, you know,
link |
many people have lost their jobs based on tweets.
link |
The short latency between thought and action
link |
and distribution of one's thoughts is incredible.
link |
And I'm not just talking about people
link |
who apparently would have poor prefrontal top-down control.
link |
This is geek speak, by the way,
link |
for people that lack impulse control.
link |
But high-level academics,
link |
I'm not gonna point fingers at anyone,
link |
but examples of where you see these tweets
link |
and you go, what were they thinking?
link |
So presumably there's an optimal strategy
link |
between the thought, speech, motor pathway,
link |
especially when the motor pathway engages communication
link |
with hundreds of thousands of people.
link |
And retweets in particular,
link |
and the cut and paste function and the screenshot function
link |
are often the reason why speech propagates.
link |
So to me, it's a little eerie
link |
that just that the neural circuitry can do this
link |
and that we are catching up a little bit more slowly
link |
to the technology,
link |
and you've got these casualties of that mismatch.
link |
I think that's a good adjective to use,
link |
the casualties of what's going on.
link |
Because yes, it is the case with texting,
link |
what you're really losing there
link |
is less so the ability to write,
link |
but more the ability to interpret what is being written.
link |
And you can undeterpit something that somebody means.
link |
On the flip side of that,
link |
when if somebody's writing something very quick,
link |
they could be writing instinctually,
link |
more instinctually, their true meaning.
link |
And they don't have time to modify and color code
link |
what they're trying to say.
link |
And that's what they really feel
link |
as opposed to say in a more nuanced way.
link |
So I think both sides of that casualty are present.
link |
And that's a downturn, an unintended negative consequence
link |
of short word communication.
link |
Yeah, I agree that this whole phenomenon
link |
could be netting people that normally
link |
would only say these things out loud
link |
once inside the door of their own home or not at all.
link |
It's an interesting time that we're in
link |
vis-a-vis speech and language and motor patterns.
link |
So part of the human evolution for language.
link |
I think this is all part of our evolution.
link |
So for those of you thinking terrible thoughts,
link |
please put them in the world and be a casualty.
link |
And for those of you that are not,
link |
please be very careful with how proficient
link |
your thought to language to motor action goes.
link |
Maybe the technology companies should install some buffers,
link |
some AI-based buffers.
link |
Right, that's taking some EEG signals from your brain
link |
while you're texting to say,
link |
okay, this is not a great thought, slow down.
link |
Right, this doesn't reflect your best state.
link |
That brings me to what was going to be
link |
the next question anyway, which is,
link |
we are quickly moving toward a time
link |
where there will be an even faster transition
link |
from thought to speech to motor output
link |
and maybe won't require motor output.
link |
What I'm referring to here is some of the incredible work
link |
of our colleagues, Eddie Chang at UCSF
link |
and others who are taking paralyzed human beings
link |
and learning to translate the electrical signals
link |
of neurons in various areas,
link |
including speech and language areas
link |
to computer screens that type out
link |
what these people are thinking.
link |
In other words, paralyzed people
link |
can put their thoughts into writing.
link |
That's a pretty extreme and wonderful example
link |
of recovery of function that is sure to continue to evolve.
link |
But I think we are headed toward a time
link |
not too long from now where my thoughts
link |
can be translated into words on a page
link |
if I allow that to happen.
link |
Yeah, so, and Eddie Chang's work,
link |
which I admire quite a bit and cite in my papers,
link |
I think he's really one of those at the leading edge
link |
of trying to understand within humans
link |
the neurobiology of speech.
link |
And he may not say it directly,
link |
but I talked to him about this,
link |
it supports this idea that the speech circuit
link |
in the separate language module,
link |
I don't really think that there's a separation there.
link |
So with that knowledge, yes,
link |
in putting electrodes in the human brain
link |
and then translating those electrical signals
link |
to speech currents, yeah,
link |
we can start to tell what is that person thinking.
link |
Why, because we often think in terms of speech
link |
and without saying words.
link |
And that's a scary thought.
link |
And now imagine if you can now translate those
link |
into a signal that transmits something wirelessly
link |
and someone from some distant part of the planet
link |
is hearing your speech from a wireless signal
link |
without you speaking.
link |
So probably that won't be done in an ethical way,
link |
who knows, but I mean,
link |
the ethics of doing that probably might not happen,
link |
but who knows, we have these songbirds,
link |
we apply the same technique to them,
link |
we can start to hear what they're singing
link |
in their dreams or whatever,
link |
even though they don't produce sound.
link |
So we can find out by testing on them.
link |
It's coming, one way or another, it's coming.
link |
For those listening who are interested
link |
in getting better at speaking and understanding languages,
link |
are there any tools that you recommend?
link |
And here again, I realize you're not a speech therapist,
link |
but here I'm not thinking about ameliorating
link |
any kind of speech deficiency.
link |
I'm thinking, for instance,
link |
do you recommend that people read different types of writing?
link |
Would you recommend that people learn how to dance
link |
in order to become better at expressing themselves verbally?
link |
And feel free to have some degrees of freedom
link |
These are obviously not peer-reviewed studies
link |
that we're referring to, although there may be,
link |
but I'm struck by the number of things
link |
that you do exceedingly well,
link |
and I can't help but ask, well, the singing,
link |
which I realize it may,
link |
your brother didn't pay me to say this,
link |
may not be quite as good as your brother's yet,
link |
but you'll surpass him, I'm guessing,
link |
at some point in getting that.
link |
Exactly, there you go.
link |
You know, should kids learn how to dance
link |
and read hard books and simple books?
link |
What do you recommend?
link |
Should adults learn how to do that?
link |
Everyone wants to know how to keep their brain
link |
working better, so to speak,
link |
but also I think people want to be able to speak well,
link |
and people want to be able to understand well.
link |
Yeah, so what I've discovered personally, right,
link |
is that, so when I switched from pursuing a career
link |
in science from a career in dance,
link |
I thought one day I would stop dancing,
link |
but I haven't because I find it fulfilling for me,
link |
just as a life experience.
link |
So ever since I started college,
link |
my late teens and early 20s,
link |
I kept dancing even till this day,
link |
and there have been periods of time
link |
like during the pandemic,
link |
where I slowed down on dancing and so forth.
link |
And when you do that, you realize,
link |
okay, there are parts of your body
link |
where your muscle tone decreases a little bit
link |
and somewhat, or you could start to gain weight.
link |
I somehow don't gain weight that easily,
link |
and I think it's related to my dance,
link |
if that's meaningful to your audience.
link |
But what I found is, in science,
link |
we like to think of a separation between movement
link |
and action and cognition.
link |
And there is a separation between perception
link |
and production, cognition being perception,
link |
production being movement, right?
link |
But if the speech pathways is next to the movement pathways,
link |
what I discover is by dancing, it is helping me think.
link |
It is helping keeping my brain fresh.
link |
It's not just moving my muscles.
link |
I'm moving or using the circuitry in my brain
link |
to control a whole big body.
link |
You need a lot of brain tissue to do that.
link |
And so I argue, if you wanna stay cognitively intact
link |
into your old age, you better be moving.
link |
And you better be doing it consistently,
link |
whether it's dancing, walking, running,
link |
and also practicing speech, oratory speech and so forth,
link |
or singing, is controlling the brain circuits
link |
that are moving your facial musculature.
link |
And it's gonna keep your cognitive circuits also in tune.
link |
And I'm convinced of that from my own personal experience.
link |
For me, long, slow runs are a wonderful way
link |
to kind of loosen the joints for long podcasts,
link |
especially the solo podcasts,
link |
which can take many hours to record.
link |
And without those long, slow runs,
link |
at least the day before or even the morning of,
link |
I don't think I could do it, at least not as well.
link |
All right, well, you're experiencing something similar.
link |
So that's an N of two.
link |
I'm tempted to learn how to dance
link |
because there are a lot of reasons to learn how to dance.
link |
People can use their imagination.
link |
I definitely wanna get the opportunity
link |
to talk about some of the newer work
link |
that you're into right now about genomes of animals.
link |
As you perhaps can tell
link |
from my quite authentic facial expressions,
link |
I adore the animal kingdom.
link |
I just find it amazing.
link |
And it's the reason I went into neurobiology, in part.
link |
So many animals, so many different patterns of movement,
link |
so many body plans, so many specializations.
link |
What is the value of learning the genomes
link |
of all these animals?
link |
I can think of conservation-based schemes
link |
of trying to preserve these precious critters,
link |
but what are you doing with the genomes of these animals?
link |
What do you wanna understand about their brain circuits?
link |
And how does this relate to some of the discussion
link |
we've been having up until now?
link |
I've gotten very heavily involved in genomes,
link |
not just to get at an individual gene
link |
involved in the trait of interest, like spoken language,
link |
but I realize that nature has done
link |
natural experiments for us.
link |
With all these species out there with these various traits,
link |
and the one that I'm studying, like vocal learning,
link |
has evolved multiple times among the animal kingdom.
link |
Even if it's rare, it's multiple times.
link |
And the similar genetic changes occurred in those species.
link |
But to find out what those genetic changes
link |
that are associated with the trait of interest,
link |
and not some other trait like flying in birds
link |
as opposed to singing,
link |
you have to do what's called comparative genomics,
link |
even in the context of studying the brain.
link |
And you need their genomes to compare the genomes
link |
and do like a GWAS, a genome-wide association study,
link |
not just within a species like humans,
link |
but across species.
link |
And so you need good genomes to do that.
link |
Plus, I've discovered I'm also interested
link |
in evolution and origins.
link |
How did these species come about a similar trait
link |
in the last 300 million years or 60 million years,
link |
depending on who you're talking about?
link |
And you need a good phylogenetic tree to do that.
link |
And to get a good phylogenetic tree,
link |
you also need their genomes.
link |
And so because of this,
link |
I got involved in large-scale consortiums
link |
and produced genomes of many different species,
link |
including my vocal learners and their closest relatives
link |
But I couldn't convince the funding agencies
link |
to give me the money to do that just for my own project.
link |
But when you get a whole bunch of people together
link |
who wanna study various traits,
link |
heart disease or loss and gain of flight and so forth,
link |
suddenly we all need lots of genomes to do this.
link |
And so now that got me into a project
link |
to lead something called the Vertebrate Genomes Project
link |
to eventually sequence all 70,000 species on the planet.
link |
And Earth Biogenome Project, all eukaryotic species,
link |
all 2 million of them.
link |
And to no longer be in a situation
link |
where I wish I had this genome,
link |
now we have the genetic code of all life on the planet,
link |
create a database of all their traits
link |
and find the genetic association with everything out there
link |
that makes a difference from one species to another.
link |
One more piece of the equation to add to this story
link |
is what I didn't realize as a neuroscientist
link |
were that these genomes are not only incomplete,
link |
but they have lots of errors in them.
link |
False gene duplications where mother and father chromosomes
link |
were so different from each other
link |
that the genome algorithm, assembly algorithms,
link |
treated them as two different genes
link |
in this part of the chromosome.
link |
So there are a lot of these false duplicated genes
link |
that people were thought were real, but were not,
link |
or missing parts of the genome
link |
because the enzymes used to sequence the DNA
link |
couldn't get through this regulatory region
link |
that folded up on itself and made it hard to sequence.
link |
And so I end up in these consortiums
link |
pulling in the genome sequencing companies
link |
developing the technology to work with us
link |
to improve it further.
link |
And the computer science guys
link |
who then take that data and that technology
link |
and try to make the complete genomes
link |
and make the algorithms better
link |
to produce what we now just did recently,
link |
led by an effort by Adam Philippi,
link |
is the first human telomere to telomere genome
link |
with no errors, all complete, no missing sequence.
link |
And now we're trying to do the same thing
link |
with vertebrates and other species.
link |
Actually, we improved that before we got
link |
to what we call telomere to telomere,
link |
from one end of the chromosome to another.
link |
And what we're discovering is in this dark matter
link |
of the genome that was missing before,
link |
turns out to be some regulatory regions
link |
that are specialized in vocal learning species
link |
and we think are involved in developing speech circuits.
link |
Incredible, so much to learn and that we're going to learn
link |
from this information.
link |
Early on in these genome projects and connectome projects,
link |
I confess I was a little bit cynical.
link |
This would be about 10, 15 years ago.
link |
I thought, okay, necessary, but not sufficient for anything.
link |
We need it, but it's not clear what's going to happen.
link |
But you just gave a very clear example
link |
of what we stand to learn from this kind of information.
link |
And I know from the conservation side,
link |
there's a huge interest in this
link |
because even though we would prefer
link |
to keep all these species alive rather than clone them,
link |
these sorts of projects do offer the possibility
link |
of potentially recreating species that were lost
link |
due to our own ignorance or missteps or what have you.
link |
Yes, and along those lines,
link |
because we got involved in genomics,
link |
some of the first species that we start working on
link |
are critically endangered species.
link |
And I'm doing that not only for perspectives
link |
to understand their brains
link |
and the genes involved in their brain function,
link |
but I feel like it's a moral duty.
link |
So the fact that now I've become more involved
link |
in genome biology and have helped develop these tools
link |
for more complete genomes,
link |
let's capture their genetic code now before they're gone.
link |
And could we use that information to resurrect the species
link |
at some future time, if not in my lifetime,
link |
in some time in the future and generations ahead of us?
link |
And so in anticipation of that,
link |
we created a database we call the Genome Arc,
link |
and no pun intended, like NOAA's arc,
link |
meant to store the genetic code
link |
as complete genome assemblies as possible
link |
for all species on the planet to be used for basic science,
link |
but also some point in the future.
link |
And because of that,
link |
funding agencies or private foundations
link |
that are interested in conservation
link |
have been reaching out to me now, a neuroscientist,
link |
to help them out in producing high quality genome data
link |
of endangered species that they can use,
link |
like Revive and Restore,
link |
who want to resurrect the passenger pigeon,
link |
or Colossal, who wants to resurrect the wooly mammoth.
link |
And so we're producing high quality genomes for these groups
link |
for their conservation projects.
link |
What a terrific and important initiative.
link |
And I think for those listening today,
link |
they now certainly understand the value
link |
of deeply understanding the brain structures
link |
and genomes of different species,
link |
because I confess,
link |
even though I knew a bit of the songbird literature,
link |
and I certainly understand
link |
that humans have speech and language,
link |
I had no idea that there was so much convergence
link |
of function, structure, and genomes.
link |
And to me, I feel a lot more like an ape
link |
than I do a songbird.
link |
And yet here we are with the understanding
link |
that there's a lot more similarity
link |
between songbirds and humans
link |
than I certainly ever thought before.
link |
Yeah, something very close to home for us humans,
link |
I can give you an example of, is evolution of skin color.
link |
In skin color, we use it, unfortunately,
link |
for racism and so forth.
link |
We use it also for good things,
link |
to let in more light or let out less light,
link |
depending on the part of the planet
link |
our population evolved in.
link |
And most people think dark-skinned people
link |
all evolved from the same dark-skinned person,
link |
and light-skinned people
link |
all evolved from the same light-skinned person,
link |
but that's not the case.
link |
Dark skin and light skin amongst humans
link |
has evolved independently multiple times,
link |
like in the Pacific Islands versus Africa.
link |
And it's just depending on the angle of light
link |
hitting the Earth,
link |
as to whether you need more protection from the sun
link |
or less protection,
link |
that's also associated with vitamin D synthesis in the skin.
link |
And so, and each time
link |
where a darker or lighter skin evolved independently,
link |
it hit the same gene.
link |
You know, the melatonin receptors, that's right, yes, yeah.
link |
Genes that are involved in melanin formation.
link |
And so, those genes evolved some of the same mutations,
link |
even in different species.
link |
It's not just humans.
link |
In equatorial regions, there are darker-skinned animals
link |
than going away from the equator.
link |
All right, I think of arctic foxes and things like that.
link |
Yes, that's right, that's right.
link |
Polar bears, you know.
link |
And so, some of the same genes are used
link |
in an evolutionary perspective to evolve in a similar way
link |
within and across species.
link |
And that's the same thing happening in the brain too.
link |
Language is no exception.
link |
Well, I have to say, as somebody who is a, you know,
link |
career neuroscientist, but as I mentioned several times now,
link |
who also adores the animal kingdom,
link |
but is also obsessed with speech and language
link |
and at a distance, not as a practitioner of music and dance,
link |
this has been an incredible conversation
link |
and opportunity for me to learn.
link |
I know I speak for a tremendous number of people,
link |
and I just really want to say thank you
link |
for joining us today.
link |
You are incredibly busy.
link |
It's clear from your description of your science
link |
and your knowledge base that you are involved
link |
in a huge number of things, very busy.
link |
So thank you for taking the time to speak to all of us.
link |
Thank you for the work that you're doing,
link |
both on speech and language,
link |
but also this important work on genomes
link |
and conservation of endangered species and far more.
link |
And I have to say, if you would agree to come back
link |
and speak to us again sometime,
link |
I'm certain that if we were to sit down
link |
even six months or a year from now,
link |
there's going to be a lot more to come.
link |
Yeah, we have some things cooking.
link |
And thank you for inviting me here
link |
to get the word out to the community
link |
of what's going on in the science world.
link |
Well, we're honored and very grateful to you, Eric.
link |
Thank you for joining me today
link |
for my discussion with Dr. Eric Jarvis.
link |
If you'd like to learn more about his laboratory's work,
link |
you can go to Jarvis Lab,
link |
spelled J-A-R-V-I-S, lab, all one word, jarvislab.net,
link |
and there you can learn about all the various studies
link |
taking place in his laboratory,
link |
as well as some of the larger overarching themes
link |
that are driving those studies,
link |
including studies on human genomics and animal genomics
link |
that surely are going to lead
link |
to the next stage discoveries of how we learn
link |
and think about and indeed use language.
link |
If you're learning from and are enjoying this podcast,
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please subscribe to our YouTube channel.
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That's a simple, zero-cost way to support us.
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Please also subscribe to the podcast on Spotify and Apple.
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And on both Spotify and Apple,
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I'd also like to point out that the Huberman Lab Podcast
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And last, but certainly not least,
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I'll see you in the next one.