An Interview with Mark Changizi: Culture Harnessing the Brain

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I’m delighted today to present an interview with Mark Changizi, the noted cognitive scientist and author. Changizi has a forthcoming book Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man, where he examines how culture can have such an impact on people.

This book represents a broadening of his previous research, which has focused on vision, cognition, and brain complexity.

His research aims to grasp the ultimate foundations underlying why we think, feel and see as we do. Focusing on “why” questions, he has made important discoveries on why we see in color, why we see illusions, why we have forward-facing eyes, why letters are shaped as they are, why the brain is organized as it is, why animals have as many limbs and fingers as they do, and why the dictionary is organized as it is.

Changizi is currently Director of Human Cognition at 2AI Labs, “Researching the mind, what it does, and where it’s headed.” Changizi’s book The Vision Revolution was named one of New Scientist’s Top Science Books of 2009. He provides an excellent (and delightfully succinct) description of it in his post on How to Write a Popular Science Book:

It’s not merely that [these authors] write well, but that they’re making a scientific case for their viewpoint. …and you and I get to watch.

And so that’s what I did in The Vision Revolution, take the reader along as I lay out the case for a radical re-thinking of how we see. Color vision evolved for seeing skin and the underlying emotions, not for finding fruit. Forward-facing eyes evolved for seeing better in forests, not for seeing in depth. Illusions are due to our brain’s attempt to correct for the neural eye-to-brain delay, so as to “perceive the present.” And our ability to read is due to writing having culturally evolved to make written words look like natural objects, just what our illiterate visual system is competent at processing.

Changizi has his own blog, where his last post took on color perception: Is Your Red and My Red the Same? His guest post for PLoS Blogs, I’m Not Only the Red Club President, I’m a Client, extends the red theme, providing a humorous take on research showing that wearing red might increase your attractiveness.

Not enough? Changizi also has a Psychology Today blog, Nature, Brain and Culture. His recent piece Why Humans Are So Smart… And Groovy was what prompted me to get in touch with him, as I wanted to hear more about his ideas about how culture is shaped to the brain:

How, then, is it that we are doing so many strange non-ape-ish things? We carry out all sorts of behaviors you shouldn’t see apes doing not because we apes have been reshaped, but because culture has gone out of its way to shape itself to fit our groovy human self. In particular, culture has shaped itself to be “like nature,” thereby best harnessing our ancient inflexible brains for doing something they weren’t designed for, like successfully ordering coffee.

We conducted this interview over the last few days by email.

Daniel Lende: So, Mark, tell me about your forthcoming book Harnessed.

Mark Changizi: Language and the arts are the centerpieces of what we humans are proud of. They are what we gloat to the other apes about. But how did we come to have language and art, and thereby stand so markedly apart from the rest of the animal world?

Answers traditionally come from one of two opposing poles.

The first view is that language and/or the arts are results of natural selection, and so we now have instincts for them: language instincts, music instincts, art instincts.

The opposing view is that, instead, we evolved to be highly plastic general-purpose learners who can train ourselves on loads of cultural artifacts evolution never intended for our brain, language and the arts among them.

There is a third option, however. It agrees with the ‘instinct’ view in positing that humans aren’t especially plastic. And it agrees with the ‘general-learner’ view in positing that culture matters. It is that language and the arts culturally evolved to be shaped “just right” to fit into our minds. Cultural — not natural — selection is the “brains” behind our human gloating rights. This kind of ‘cultural-selection’ view also is an old one.

What is new here is my view of how culture goes about making language and the arts good for our brain: Culture’s trick is to make language and the arts “mimic nature,” just the thing our brain *is* designed to absorb.

I refer to it as “Nature Harnessing.”

The tricky part is fleshing out what one could possibly mean by “mimic nature,” and figuring out how one would go about testing it. I have made significant attempts in this regard for reading, speech, and music. The case for reading is part of my book, *The Vision Revolution*. The upcoming *Harnessed* takes up the case for speech and music.

The nature-harnessing story for these three cases is as follows…

Writing has culturally evolved so that written words tend to look like visual objects in natural scenes (in particular, natural scenes with opaque objects strewn about).

Speech has culturally evolved so that spoken words tend to sound like natural auditory events (in particular, events among solid objects).

And music has culturally evolved to sound like humans moving in our midst — music is a fictional auditory story of a person moving about in our vicinity.

The strategy in each case is to understand the structure found in the natural environment, and check whether this “natural signature” is found in the cultural artifact.

Daniel Lende: Let’s take the example of speech. How do spoken words sound like natural auditory events? And what would you say to the point made in many Introduction to Anthropology classes that the symbolic meaning of a word is not determined by the physical sound structure of that word?

[For those of you looking for more on Mark’s views on writing, see his piece The Topography of Language. On music, see this essay in The Atlantic, Where Does Music Come From?]

Mark Changizi: I’ll give you a couple starting samples of how speech has the signature sounds of natural auditory events. In particular, my claim is not, say, that speech sounds like the savanna. Rather, the class of natural sounds is a very fundamental and general one, the sounds of events among solid objects. There are lots of regularities in the sounds of solid-object physical events, and it is possible to begin working them out

For example, there are primarily three “atoms” of solid-object physical events: hits, slides and rings. Hits are when two objects hit one another, and slides where one slides along the other. Hits and slides are the two fundamental kinds of interaction. The third “atom” is the ring, which occurs to both objects involved in an interaction: each object undergoes periodic vibrations — they ring. They have a characteristic timbre, and your auditory system can usually recognize what kind of objects are involved.

For starters, then, notice how the three atoms of solid-object physical events match up nicely with the three fundamental phoneme types: plosives, fricatives and sonorants. Namely, plosives (like t, k, p, d, g, b) sound like hits, fricatives (s, sh, f, z, v) sound like slides, and sonorants (vowels and also phonemes like y, w, r, l) sound like rings.

Our mouths make their sounds *not* via the interaction of solid-object physical events. Instead, our phonemes are produced via air-flow mechanisms that *mimic* solid-object events. In fact, our air-flow sound-producing mechanisms can do *lots* more kinds of sounds, far beyond the limited range of solid-object sounds. But for language, they rein it in, and keep the words sounding like the solid-object events that are most commonly in nature, the kind our auditory system surely evolved to process efficiently.

As a second starter similarity, notice that solid-object events do not occur via random sequences of hits, slides and rings. There are lots of regularities about how they interact — and that I have tested to see that they apply in language — but a first fairly obvious one is this… Events are essentially sequences of hits and slides. That is, the *causal* sequence concerns the hits and the slides, not the rings. “The ball hit the table and bounced up, and then bumped into the wall, hit the ground again, and slid to a stop.”

Rings happen during all events, but they happen “for free” at each physical interaction. Solid-object events are sequences of the form, , where ‘interaction’ can have hit or slide in it. This is perhaps the most fundamental “grammatical rule” of solid-object physical events, and it looks suspiciously like the most fundamental morphological rule in language: the syllable, the fundamentally universal version which is the CV form, usually a plosive-or-fricative (ahem, a physical interaction) followed by a sonorant (ahem, a ring).

In my research I continue to work out the regularities found among solid-object physical events, and in each case ask if the regularity can be found in the sounds of speech.

As for “the symbolic meaning of a word is not determined by the physical sound structure of that word,” indeed, I agree. My own theory doesn’t propose this, but only that speech has come to have the signature structures found among solid-object events generally, thereby “sliding” easily into our auditory brain. (That said, I do think there are lot more of the “kaka” / “bobo” cross-modal metaphors out there, and they can be explained by better understanding the ecological regularities.)

Daniel Lende: That’s fascinating. Many people believe that thought and ideas happen only in people’s heads. I often emphasize to students that language is a physical thing – sounds travel between people and these are as physical and real as neural circuits. Communication is more than two brains mirroring each other. And hence we cannot understand something like culture only by looking at what is inside people’s heads. Those physical sounds going between people matter too, and are part of how culture happens.

That leads me to my next question. What do these regularities in both natural auditory events and speech tell us about the co-evolution of our brains and culture?

Mark Changizi: When you say, “Those physical sounds going between people matter too, and are part of how culture happens,” I might flip it around. That is, your quote suggests that culture happens, or relies upon, speech and language. But, the other-way-around is that speech and language rely upon culture, namely, cultural evolution having shaped speech to harness (“nature-harness”) our brain and auditory system.

In reality, it went both ways. Cultural transmission and evolution can happen without language, but probably gets more efficient in its ability to “design” for the mind once language is part of the story. That is, surely there is a co-evolution between the culture and language.

As for the co-evolution of our brains and culture which you ask about, the view I am suggesting is that there has been potentially little or no co-evolution. Our earliest Homo sapiens ancestors — with the same brains as us — had little culture to speak of, and little or no language either. Once cultural evolution got up and running, as a “design” mechanism it gets things done orders of magnitude faster than natural selection, and so in a relative blink of an eye (on the order of a hundred thousand years or so), cultural evolution quickly figured out how to harness language-less, illiterate and amusical Homo sapiens brains for language, writing and music. Homo sapiens became more like you and I, biologically identical to our Homo sapiens ancestors, but harnessed by culture to become something quite different: human.

Daniel Lende: Let me see if I have this straight. As cultural evolution begins, it adapts itself to the biological bases of people, for example, how sound production and then language get funneled into an adaptive space based on how our brain and auditory systems work. In turn, that matching then accelerates the ability of culture to harness and shape people in quite different ways from what existed before. Is that a fair characterization? And what role would neural plasticity play in this?

Mark Changizi: On the characterization of the feedback driving cultural evolution (cultural evolution leads to harnessing, and better-harnessed people are better “cogs” in the machine of cultural evolution), surely something like that must be going on. But I have no real insight on the nature of the feedback.

Cultural evolution is a mish-mash of selective mechanisms, and I pretty much just pretend it is a black box for my purposes. …my “nature-harnessing” claim is only that one of the more fundamental tricks up cultural evolution’s sleeve for funneling modern artifacts into our ancient biology is shaping those modern artifacts to be “like nature.”

On neural plasticity, some degree of neural plasticity is important, but my view is that our human plasticity wouldn’t stand out among the other mammals. Having innate, highly specialized brain mechanisms doesn’t mean the brain is not plastic. Rather, it means that an animal is endowed with learning mechanisms specifically designed to learn particular kinds of stuff. General-purpose, universal learning machines are terrible at learning anything — in fact, there’s no such thing as a “universal learning machine.”

So, in my view our visual and auditory systems (and all sensory systems) have an essential plasticity needed to learn to recognize the natural environments the animal inhabits. But these mechanisms will generally be comparably terrible at learning utterly unnatural kinds of stimuli.

To get language and music into us, I claim, the key plasticity that mattered was not some special human plasticity, but “cultural plasticity,” i.e., the ability for cultural evolution to “learn” how to harness us.

Daniel Lende: Readers of Neuroanthropology are people interested in integrating neuroscience and anthropology, and using that to understand the human condition a bit better. What’s the main take-home message you hope these readers get from your work?

Mark Changizi: Maybe I am preaching to the choir — given your readership — but I believe one cannot understand the brain without understanding its relationship to the natural ecology in which it evolved, and (mainly for the human brain) also to the culture in which it resides. Nature, brain, and culture must mutually be understood to make sense of our brain. …as well as evolution, both natural selection and cultural selection.

And, in particular, my view is summarized somewhat as…

Nature ← Brain ← Culture

…where the arrows are not causal, but showing the “explanatory source” of each thing. So, why is the brain structured as it is? Because it was selected to be a “fit for nature.” And why is culture the way it is? Because it was selected to be a “fit for the brain.”

And my “nature-harnessing” hypothesis is that, because culture is “designed” for the brain and the brain “designed” for nature, we can get a lot of theoretical mileage by skipping the middle man — the brain — and positing that cultural artifacts got shaped like nature. That is, where “brain” has been removed from the diagram…

Nature ← Culture.

In reality, the brain still sits “in between,” but as a simplification it is a boon for a theorist, because it is much easier to work out whether cultural artifacts are shaped “like nature” than whether they are shaped well for the brain; there are often simple regularities that can be worked out in nature, but the brain is, ahem, complicated.

As for “neuroanthropology,” that’s just the sort of thing neuroscience (and maybe anthropology) needs more of.

Daniel Lende: Thanks so much, Mark. I really enjoyed this interview! And yes, anthropology does need more neuroanthropology!

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