Particles of Thought

HAKEEM: So that brings me to another research study that I heard I think a year ago. I don't think the result was a year ago. I think I heard someone speaking of it a year ago. And what that was is that it was originally thought that chimpanzees don't have the mechanical equipment for producing speech.

ERICH: Yeah. Yep.

HAKEEM: But then some study found, well actually they do, they just don't have the brain for it.

ERICH: That's right. That's right. Yes.

HAKEEM: Okay.

ERICH: Yeah. Yeah. This has been a debate over a number of years, and it includes what in the biology, in the brain, in the muscles and so forth, makes speech special.

HAKEEM: Right.

ERICH: And there are a number of different hypotheses, and this is one of them, that there's a difference in the musculature of the larynx, or that it's more descended in humans, and allowing greater airspace in the vocal tract to produce a greater variety of sounds. A lot of this has been proven not to be the case. All right?

So a colleague of mine, Tecumseh Fitch, blows air through post-mortem larynxes of humans, of chimpanzees, of monkeys. And you get similar kinds of sounds that you get in speech, when you... Phonemes, we call them different kinds of phonemes, that you get when you blow air, even through a post-mortem larynx.

HAKEEM: Wow.

ERICH: But when it's inside the living animal of a monkey, you can't get the speech sounds out of it. And why? Because it's not in the muscles, it's in the brain that makes that difference between being able to speak and not speak.

HAKEEM: So is it the case that, you have birds, do you have mammals, a different part of the family tree.

ERICH: Yep. Yep.

HAKEEM: So are the same outcomes being achieved by different brain areas? Or is it that there's some ancient ancestor that predates birds and mammals that had this particular equipment, and now it's being used in different ways to get the...

ERICH: Yep. Well, discovering these gene specializations, where the regulation is different, helped us answer some of the questions that you just asked.

HAKEEM: Okay.

ERICH: And putting it all together, the story that I've come up with is that all vertebrates have the ability to learn how to move, and what happened in us humans, and the song learning birds, dolphins I believe as well, is that these brain pathways that control learned movement of the body, are duplicating themselves to control the hands, the chest, the feet, and so forth during embryonic development.

And in us humans, and the vocal learning birds, the brain pathway duplicated one more time, and now got hooked up to the muscles of the larynx, and the jaw and so forth, to control sound production, to learn how to imitate sounds. And we already have auditory input from the hearing pathway going into the movement pathway. If you are going to learn how to move, you got to learn to move to the sounds that you hear, learn to move away from sounds and so forth.

HAKEEM: Wow. Right.

ERICH: And so this auditory input is already happening.

HAKEEM: Yeah.

ERICH: The ability to understand complex sounds is already there.

HAKEEM: Yeah.

ERICH: All right? I think consciousness is already there. And yes, language evolved more recently, spoken language. We call this brain evolution by brain pathway duplication, like gene duplication, a whole brain pathway duplicates, connects to the vocal organs, and now you get spoken... Like speech, basically.

HAKEEM: Holy cow.

ERICH: And spoken language.

HAKEEM: Talking about taking something that already exists, and-

ERICH: Yeah.

HAKEEM: Yeah, yeah.

ERICH: And so this happened multiple times, and when... Each time that it happened, a certain set of genes change in their regulation in humans, and in the song learning birds. We call that convergent evolution.

HAKEEM: Right.

ERICH: All right? Because their closest relatives, like us for chimpanzees, we are their closest relatives. I mean, they're our closest relatives, too. So chimpanzees-

HAKEEM: Right. Right. Living, surviving relatives.

ERICH: The surviving-

HAKEEM: Closest surviving relatives. Yeah, yeah, right.

ERICH: Yes. That's right. Let's say what we call suboscine birds for songbirds or falcons for parrots. None of them have these brain pathways, or this gene expression specializations that we see in the vocal learning birds. So we think the whole brain pathway duplicated, the gene specializations then were evolved in a convergent manner.

HAKEEM: I see.

ERICH: And so it suggests that if vocal learning and spoken language were to evolve another half a million years from now, say in a crocodile-

HAKEEM: Yeah.

ERICH: Right?

HAKEEM: Yeah.

ERICH: Or a chimpanzee, I could tell you what the brain pathways are going to look like, and I can tell you which genes are going to change.

HAKEEM: It's predictable.

ERICH: It's predictable.

HAKEEM: Wow.

ERICH: That's right.

HAKEEM: Because you know what the rough material they have to start with is already.

ERICH: That's right.

HAKEEM: Yeah. Yeah.

ERICH: Well, because we've already seen it multiple times in multiple lineages of species, that there seems to be a basic principle, of a fundamental set of genes that needs to change in order to get vocal imitation.

HAKEEM: Right.

ERICH: All right? And in the songbirds, that was like 30 million years ago.

HAKEEM: Yeah.

ERICH: In parrots, that was 50 million years ago. In humans, it was, the most, a million years ago.

HAKEEM: Okay.

ERICH: I think with some common ancestors with Neanderthal, and Denisovan, archaic humans.

HAKEEM: So it would've been homo erectus then that had language first?

ERICH: We might go that far back.

HAKEEM: Okay.

ERICH: That would be a prediction.

HAKEEM: Okay.

ERICH: But certainly, the hominids as we call them, which are modern humans and archaic humans.

HAKEEM: Right, right, right. Wow. So you brought up this idea between hearing, speech and motion. So this is something... My niece was born in 1984, when I was in high school.

ERICH: Yeah.

HAKEEM: And you know what? Rap was new.

ERICH: Yeah.

HAKEEM: So I used to sit around, beating out beats, and my little niece, as soon as she could sit up, she would bob and dance to the little beats I was making.

ERICH: Yeah.

HAKEEM: And at the time I was a high school musician as well. It occurred to me, I was like, what is this thing with music? Why is it that we respond in such a way, we get emotional, our bodies move almost without us thinking about it to these sounds.

ERICH: Yep. Yep.

HAKEEM: Like what the hell is going on? Why? Because it seems like a lot of species are completely... They don't respond that way. Right?

ERICH: Yeah.

HAKEEM: Right?

ERICH: Yep.

HAKEEM: Have you guys figured that out? What's the-

ERICH: Yeah. One of the remarkable things, the discoveries in the last 10 to 15 years is that it's been found that only vocal learning species can learn how to dance. And when I say dance, I mean rhythmically to a beat of sound and music. And why is that the case?

HAKEEM: Yeah.

ERICH: In order to evolve the ability to imitate sounds, you need the auditory input going through your ears to have rapid integration with the movement pathway that's controlling your muscles to produce those sounds. All right? You need that tight auditory motor integration, as we call it. I think that once that tight integration occurred for the vocal organs, it contaminated the rest of the movement pathway, to now process sound in a way that controls movement, or influences movement of the other organs, of the other body parts, muscles that control the body, the arms, the legs. And so... Yep. You know, your little niece, right?

HAKEEM: Yeah, yeah, yeah.

ERICH: It has something special going on that they find in these humans, and other vocal learning species. And so, I think it's a side effect of having vocal learning. The ability to dance came about because of our ability to speak.

HAKEEM: Wow.

ERICH: Yeah.

HAKEEM: That is so deep.

ERICH: And what's remarkable is that there are several kinds of abilities that came along either for the ride, or that are evolved, that are correlated with our ability to speak. And that's one of them, is the ability to dance synchronously to a beat of music. Another is problem solving.

HAKEEM: Interesting.

ERICH: We found that the more advanced vocal learning abilities you find, let's say in a songbird species, the better you are at problem solving. All right?

HAKEEM: Interesting.

ERICH: And so, there's some cognitive ability there. And putting all this together, these abilities that are special in vocal learners, I call it the vocal learning cognitive complex, and I'm including dancing in that cognitive complex.

HAKEEM: Wow. Wow.