EDGE


EDGE 3 — January 11, 1997

THE THIRD CULTURE

"ORGANS OF COMPUTATION"
A Talk With Steven Pinker


THE REALITY CLUB

Comments by: Steven Mithen, Steven Quartz, Nicholas Humphrey, Patricia S. Churchland, Sandra Blakeslee, Steven Pinker, Nicholas Humphrey, Richard Potts


(10,736 words)


John Brockman, Editor and Publisher | Kip Parent, Webmaster

THE THIRD CULTURE



"ORGANS OF COMPUTATION"
A Talk With Steven Pinker

Introduction by John Brockman

One of the central metaphors of the third culture is computation. The computer does computation and the mind does computation. To understand what makes birds fly, you may look at airplanes, because there are principles of flight and aerodynamics that apply to anything that flies. That is how the idea of computation figures into the new ways in which scientists are thinking about
complicated systems.

At first, people who wanted to be scientific about the mind tried to treat it by looking for fundamentals, as in physics. We had waves of so-called mathematical psychology, and before that psychologists were trying to find a simple building block-an "atom"-with which to reconstruct the mind. That approach did not work. It turns out that minds, which are brains, are extremely complicated artifacts of natural selection, and as such they have many emergent properties that can best be understood from an engineering point of view.

We are also discovering that the world itself is very "kludgey"; it is made up of curious Rube Goldberg mechanisms that do cute tricks. This does not sit well with those who want science to be crystalline and precise, like Newton's pure mathematics. The idea that nature might be composed of Rube Goldberg machines is deeply offensive to people who have a strong esthetic
drive-those who say that science must be beautiful, that it must be pure, that everything should be symmetrical and deducible from first principles. That esthetic has been a great motivating force in science, since Plato.

Counteracting it is the esthetic that says the beauties of nature come from the interaction of mind-boggling complexities, and that it is complexity essentially most of the way down. The computational perspective-machines made out of machines made out of machines-is on the ascendant.

The experimental psychologist Steven Pinker is a unifier, someone who ties a lot of big ideas together. He has studied visual cognition and language acquisition in the laboratory, and was one of the first to develop computational models of how children learn the words and grammar of their first language. He has merged Chomskyan ideas about an innate language faculty with the Darwinian theory of adaptation and natural selection. Pinker also wrote one of the most influential critiques of neural-network models of the mind. His 1994 book The Language Instinct discussed all aspects of language in a unified, Darwinian framework, and in a new book he tries to do the same for the rest of the mind, explaining "what the mind is, how it evolved, and how it allows us to see, think, feel, laugh, interact, enjoy the arts, and ponder the mysteries of life." One of the central metaphors of the third culture is computation. The computer does computation and the mind does computation. To understand what makes birds fly, you may look at airplanes, because there are principles of flight and aerodynamics that apply to anything that flies. That is how the idea of computation figures into the new ways in which scientists are thinking about complicated systems.

At first, people who wanted to be scientific about the mind tried to treat it by looking for fundamentals, as in physics. We had waves of so-called mathematical psychology, and before that psychologists were trying to find a simple building block-an "atom"-with which to reconstruct the mind. That approach did not work. It turns out that minds, which are brains, are extremely complicated artifacts of natural selection, and as such they have many emergent properties that can best be understood from an engineering point of view.

We are also discovering that the world itself is very "kludgey"; it is made up of curious Rube Goldberg mechanisms that do cute tricks. This does not sit well with those who want science to be crystalline and precise, like Newton's pure mathematics. The idea that nature might be composed of Rube Goldberg machines is deeply offensive to people who have a strong esthetic drive-those who say that science must be beautiful, that it must be pure, that everything should be symmetrical and deducible from first principles. That esthetic has been a great motivating force in science, since Plato.

Counteracting it is the esthetic that says the beauties of nature come from the interaction of mind-boggling complexities, and that it is complexity essentially most of the way down. The computational perspective-machines made out of machines made out of machines-is on the ascendant.

The experimental psychologist Steven Pinker is a unifier, someone who ties a lot of big ideas together. He has studied visual cognition and language acquisition in the laboratory, and was one of the first to develop computational models of how children learn the words and grammar of their first language. He has merged Chomskyan ideas about an innate language faculty with the Darwinian theory of adaptation and natural selection. Pinker also wrote one of the most influential critiques of neural-network models of the mind. His 1994 book The Language Instinct discussed all aspects of language in a unified, Darwinian framework, and in a new book he tries to do the same for the rest of the mind, explaining "what the mind is, how it evolved, and how it allows us to see, think, feel, laugh, interact, enjoy the arts, and ponder the mysteries of life."-

JB


"ORGANS OF COMPUTATION"

A Talk With Steven Pinker

BROCKMAN: How does one even begin to explain something as complicated as the human mind?

PINKER: I think the key to understanding the mind is to try to "reverse-engineer" it — to figure out what natural selection designed it to accomplish in the environment in which we evolved. In my new book, How the Mind Works, I present the mind as a system of "organs of computation" that allowed our ancestors to understand and outsmart objects, animals, plants, and each other.

BROCKMAN: How is that approach different from what intellectuals currently believe?

PINKER: Most of the assumptions about the mind that underlie current discussions are many decades out of date. Take the hydraulic model of Freud, in which psychic pressure builds up in the mind and can burst out unless it's channeled into appropriate pathways. That's just false. The mind doesn't work by fluid under pressure or by flows of energy; it works by information. Or, look at the commentaries on human affairs by pundits and social critics. They say we're "conditioned" to do this, or "brainwashed" to do that, or "socialized" to believe such and such. Where do these ideas come from? From the behaviorism of the 1920's, from bad cold war movies from the 1950's, from folklore about the effects of family upbringing that behavior genetics has shown to be false. The basic understanding that the human mind is a remarkably complex processor of information, an "organ of extreme perfection and complication," to use Darwin's phrase, has not made it into the mainstream of intellectual life.

BROCKMAN: What makes you say that the mind is such a complex system?

PINKER: What should impress us about the mind is not its rare extraordinary feats, like the accomplishments of Mozart or Shakespeare or Einstein, but the everyday feats we take for granted. Seeing in color. Recognizing your mother's face. Lifting a milk carton and gripping it just tight enough that it doesn't drop but not so tight that you crush it, while rocking it back and forth to gauge how much milk is in the bottom just from the tugs on your fingertips. Reasoning about the world—what will and won't happen when you open the refrigerator door. All of these things sound mundane and boring, but they shouldn't be. We can't, for example, program a robot to do any of them! I would pay a lot for a robot that would put away the dishes or run simple errands, but I can't, because all of the little problems that you'd need to solve to build a robot to do that, like recognizing objects, reasoning about the world, and controlling hands and feet, are unsolved engineering problems. They're much harder than putting a man on the moon or sequencing the human genome. But a four-year-old solves them every time she runs across the room to carry out an instruction from her mother.

I see the mind as an exquisitely engineered device—not literally engineered, of course, but designed by the mimic of engineering that we see in nature, natural selection. That's what "engineered" animals' bodies to accomplish improbable feats, like flying and swimming and running, and it is surely what "engineered" the mind to accomplish its improbable feats.

BROCKMAN: What does that approach actually buy you in studying how the mind works?

PINKER: It tells you what research in psychology should be: a kind of reverse engineering. When you rummage through an antique store and come across a contraption built of many finely meshing parts, you assume that it was put together for a purpose, and that if you only understood that purpose, you'd have insight as to why it has the parts arranged the way they are. That's true for the mind as well, though it wasn't designed by a designer but by natural selection. With that insight you can look at the quirks of the mind and ask how they might have made sense as solutions to some problem our ancestors faced in negotiating the world. That can give you an insight into what the different parts of the mind are doing.

Even the seemingly irrational parts of the mind, like strong passions—jealousy, revenge, infatuation, pride—might very well be good solutions to problems our ancestors faced in dealing with one another. For example, why do people do crazy things like chase down an ex-lover and kill the lover? How could you win someone back by killing them? It seems like a bug in our mental software. But several economists have proposed an alternative. If our mind is put together so that under some circumstances we are compelled to carry out a threat regardless of the costs to us, the threat is made credible. When a person threatens a lover, explicitly or implicitly, by communicating "If you ever leave me I'll chase you down," the lover could call his bluff if she didn't have signs that he was crazy enough to carry it out even though it was pointless. And so the problem of building a credible deterrent into creatures that interact with one another leads to irrational behavior as a rational solution. "Rational," that is, with respect to the "goal" of our genes to maximize the number of copies of themselves. It isn't "rational," of course, with respect to the goal of whole humans and societies to maximize happiness and fairness.

Another example is the strange notion of happiness. What is the psychological state called "happiness" for? It can't be that natural selection designed us to feel good all the time out of sheer good will. Presumably our brain circuits for happiness motivate us to accomplish things that enhance biological fitness. With that simple insight one can make some sense of some of the puzzles of happiness that wise men and women have noted for thousands of years. For example, directly pursuing happiness is often a recipe for unhappiness, because our sense of happiness is always calibrated with respect to other people. There is a Yiddish expression: when does a hunchback rejoice? When he sees one with a bigger hump.

Perhaps we can make sense of this by putting ourselves in the shoes of the fictitious engineer behind natural selection. What should the circuit for happiness be doing? Presumably it would be assessing how well you're doing in your current struggle in life—whether you should change your life and try to achieve something different, or whether you should be content with what you're achieved so far, for example, when you are well-fed, comfortable, with a mate, in a situation likely to result in children and so on. But how could a brain be designed in advance to assess that? There's no absolute standard for well-being. A Paleolithic hunter-gatherer should not have fretted that he had no running shoes or central heating or penicillin. How can a brain know whether there is something worth striving for? Well, it can look around and see how well off other people are. If they can achieve something, maybe so can you. Other people anchor your well-being scale and tell you what you can reasonably hope to achieve.

Unfortunately, it gives rise to a feature of happiness that makes many people unhappy—namely, you're happy when you do a bit better than everyone around you and you're unhappy when you're doing worse. If you look in your paycheck envelope and you discover you've got a five percent raise you'd be thrilled, but if you discover that all your co-workers got a ten percent raise you'd be devastated.

Another paradox of happiness is that losses are felt more keenly than gains. As Jimmy Connors said, "I hate to lose more than I like to win." You are just a little happy if your salary goes up, but you're really miserable if your salary goes down by the same amount. That too might be a feature of the mechanism designed to attain the attainable and no more. When we backslide, we keenly feel it because what we once had is a good estimate of what we can attain. But when we improve we have no grounds for knowing that we are as well off as we can hope to be. The evolutionary psychologist Donald Campbell called it "the happiness treadmill." No matter how much you gain in fame, wealth, and so on, you end up at the same level of happiness you began with—though to go down a level is awful. Perhaps it's because natural selection has programmed our reach to exceed our grasp, but by just a little bit.

BROCKMAN: How do you differ from other people who have written about the mind, like Dan Dennett, John Searle, Noam Chomsky, Gerald Edelman, or Francis Crick?

PINKER: For starters, I place myself among those who think that you can't understand the mind only by looking directly at the brain. Neurons, neurotransmitters, and other hardware features are widely conserved across the animal kingdom, but species have very different cognitive and emotional lives. The difference comes from the ways in which hundreds of millions of neurons are wired together to process information. I see the brain as a kind of compute r—not like any commercial computer made of silicon, obviously, but as a device that achieves intelligence for some of the same reasons that a computer achieves intelligence, namely processing of information. That places me with Dennett and Chomsky (though the three of us disagree about much else), and in disagreement with people like Searle, who denies that the brain can be understood as an information-processor and insists it can only be understood in terms of physiology. Edelman and Crick would not state their views in terms as extreme as Searle's but they, too, are not entirely sympathetic to the computational theory of mind.

Like Dennett and Searle, but unlike Chomsky, I believe that natural selection is the key to explaining the structure of the mind—that reverse-engineering in the light of natural selection is the key to answering why our thoughts and feelings are structured as they are.

I also believe that the mind is not made of Spam—it has a complex, heterogeneous structure. It is composed of mental organs that are specialized to do different things, like seeing, controlling hands and feet, reasoning, language, social interaction, and social emotions. Just as the body is divided into physical organs, the mind is divided into mental organs. That puts me in agreement with Chomsky and against many neural network modelers, who hope that a single kind of neural network, if suitably trained, can accomplish every mental feat that we do. For similar reasons I disagree with the dominant position in modern intellectual life—that our thoughts are socially constructed by how we were socialized as children, by media images, by role models, and by conditioning.

BROCKMAN: But haven't there been objections to the computer metaphor of the mind?

PINKER: Some critics think it is an example of our mindless incorporating the latest technology into our theories. The objection goes: when telephone switchboards first came into existence, people thought the mind was a switchboard; before that, when fancy water-powered mechanical toys were the rage, people said the mind was a hydraulic machine, and so on. Of course there's a danger is taking metaphors too literally, but when you're careful, mechanical metaphors really do increase our understanding. The heart and blood vessels really can be better understood by thinking about pumps and pipes, and the switchboard metaphor offers a clearer understanding of the nerves and spinal cord than the models that came before it.

And I think the theory of computation, and in some cases real computers, do offer principles that are essential to understanding how the mind works. The idea is not that the mind is like a commercial computer; it's that minds and computers work by some of the same principles. When engineers first came to understand flight as they designed airplanes, it provided insight as to how birds fly, because principles of aerodynamics, like shape of an airfoil or the interplay of lift and drag, are applicable both to planes and to birds. That doesn't mean that the airplane is a good model of the birds. Birds don't have propellers and headphone jacks and beverage service, for example. But by understanding the laws that allow any device to fly, one can understand how natural devices fly. The human mind is unlike a computer in countless ways, but the trick behind computation is the trick behind thought—representing states of the world, that is, recording information, and manipulating the information according to rules that mimic relations of truth and statistical probability that hold in the world.

BROCKMAN: Haven't there also been political objections to the biological approach you are taking?

PINKER: Many people lump together the idea that the mind has a complex innate structure with the idea that differences between people have to be innate. But the ideas are completely different. Every normal person on the planet could be innately equipped with an enormous catalog of mental machinery, and all the differences between people—what makes John different from Bill—could come from differences in experience, of upbringing, or of random things that happened to them when they were growing up. To believe that there's a rich innate structure common to every member of the species is different from saying the differences between people, or differences between groups, come from differences in innate structure. Here's an example. Look at number of legs—it's an innate property of the human species that we have two legs as opposed to six like insects, or eight like spiders, or four like cats—so having two legs is innate. But if you now look at why some people have one leg, and some people have no legs, it's completely due to the environment—they lost a leg in an accident, or from a disease. So the two questions have to be distinguished. And what's true of legs is also true of the mind.

BROCKMAN: As you know, I have been increasingly interested in the growing presence of the internet and its effects on intellectual life. Do you think that what we know about the mind has any implications for how quickly computer technology will change our world?

PINKER: Computer technology will never change the world as long as it ignores how the mind works. Why did people instantly start to use fax machines, and continue to use them even though electronic mail makes much more sense? There are millions of people who print out text from their computer onto a piece of paper, feed the paper into a fax machine, forcing the guy at the other end to take the paper out, read it, and crumples it up—or worse, scan it into his computer so that it becomes a file of bytes all over again. This is utterly ridiculous from a technological point of view, but people do it. They do it because the mind evolved to deal with physical objects, and it still likes to conceptualize entities that are owned and transferred among people as physical objects that you can lift and store in a box. Until computer systems, email, video cameras, VCR's and so on are designed to take advantage of the way the mind conceptualizes reality, namely as physical objects existing at a location and impinged upon by forces, people are going to be baffled by their machines, and the promise of the computer revolution will not be fulfilled.

Part of the problem may be that our best technology comes from Japan and the manuals were written in Japanese and then translated, but I have a hunch that in Japan they have as much trouble programming the VCR as we do here. It's not just the instructions, but the design of the machines themselves, that's the problem. The machines were designed by engineers that aren't used to thinking about how the human mind works. They're used to designing machinery that is elegant by their own standards, and they don't think about how the user is going to conceptualize the machine as another object in the world and deal with it as we've been dealing with objects for hundreds of thousands of years.

BROCKMAN: Let me turn the question around. What is the significance of the Internet and today's communications revolution for the evolution of the mind?

PINKER: Probably not much. You've got to distinguish two senses of the word "evolution." The sense used by me, Dawkins, Gould, and other evolutionary biologists refers to the changes in our biological makeup that led us to be the kind of organism we are today. The sense used by most other people refers to continuous improvement or progress. A popular idea is that our biological evolution took us to a certain stage, and our cultural evolution is going to take over—where evolution in both cases is defined as "progress." I would like us to move away from that idea, because that the processes that selected the genes that built our brains are different form the processes that propelled the rise and fall of empires and the march of technology and.

In terms of strict biological evolution, it's impossible to know where, if anywhere, our species is going. Natural selection generally takes hundreds of thousands of years to do anything interesting, and we don't know what our situation will be like in ten thousand or even one thousand years. Also, selection adapts organism to a niche, usually a local environment, and the human species moves all over the place and lurches from life style to life style with dizzying speed on the evolutionary timetable. Revolutions in human life like the agricultural, industrial, and information revolutions occur so quickly that no one can predict whether the change they will have on our makeup, or even whether there will be a change.

The Internet does create a kind of supra-human intelligence, in which everyone on the planet can exchange information rapidly, a bit like the way different parts of a single brain can exchange information. This is not a new process; it's been happening since we evolved language. Even non-industrial hunter-gatherer tribes pool information by the use of language. That has given them remarkable local technologies—ways of trapping animals, using poisons, chemically treating plant foods to remove the bitter toxins, and so on. That is also a collective intelligence that comes from accumulating discoveries over generations, and pooling them amongst a group of people living at one time. Everything that's happened since, such as writing, the printing press, and now the Internet, are ways of magnifying something that our species already knew how to do, which is to pool expertise by communication. Language was the real innovation in our biological evolution; everything since has just made our words travel farther or last longer.


THE REALITY CLUB

Re: "ORGANS OF COMPUTATION"

Steven Mithen, Steven Quartz, Nicholas Humphrey, Patricia S. Churchland, Sandra Blakeslee, Steven Pinker, Nicholas Humphrey, Richard Potts


Current number of posts: 8

Post: 1 Submitted: 1-13-97
From: Steven Mithen

Asking how the quirks of the mind might have made sense as solutions to the problems that our ancestors faced in negotiating the world is a powerful strategy for working out how the mind works. But there are quirks and mega-quirks. The latter include those things that Pinker is not over impressed with, such as the accomplishments of Mozart, Shakespeare and Einstein. Well those may be rare, extra-ordinary feats but other mega-quirks are more widespread. Apparently more than 50% of the population of the USA believe in divine creation as opposed to human evolution by natural selection. The last two decades has seen the growth of fundamentalism throughout the world, even though it is precisely within this period that human evolution has become so well documented. How can the belief in super-natural beings, life after death, miraculous transformations of matter beliefs that are so resilient when faced with evidence to the contrary be explained as solutions to the problems that our ancestors faced? The archaeological evidence is quite clear that such beliefs did not arise until very recently in human evolution, a 100,000 years ago at most, and yet they dominate the minds of the majority of people alive today. Racist thought is another mega-quirk, manifest recently in the attempted genocides in Bosnia and Central Africa. Such genocide is justified on the basis that some people are less than human, a racist idea that has plagued the twentieth century and which cannot be acquired simply by processing information about those peoples behaviour. How can such racist thought be explained as solutions to the problems that our ancestors faced in their evolutionary environments? To suggest that such thoughts are the 20th century manifestation of ways of thought and behaviour that were once rationale in an ancestral environment, as one might when considering the ex-lover problem that Pinker describes, is simply incompatible with the nature of racist thought that has pervaded so much of human history (but only the very latter stages of prehistory). And tell those oppressed people that the minds of their oppressors are organs of extreme perfection (to either ancestral or modern conditions) and I suspect that they will hasten to disagree.

To make any impact on the academic or popular understanding of the mind, evolutionary psychologists need to tackle these mega-quirks rather than staying on the safe ground of explaining how the human ability to recognise faces, manipulate objects and engage in complex social relations are products of an evolutionary history. That these arise as adaptations to ancestral conditions is not seriously challenged, especially as so many of these mental attributes are shared by our living relatives. Pinkers description of lifting and squeezing the milk carton, for instance, has an uncanny resemblance to Dick Byrnes descriptions of the careful manipulation of thorny plant material by gorillas. If we are to explain the human mind as a product of biological evolution, then we must deal explicitly with those ways of thought that are unique to humans the peculiar feats of bizarre, creative and destructive thought for which all humans, not just a few individuals, have the potential. We can find such explanations, but they require us going beyond the idea that our minds are simply computational, information processing devices for solving the problems that were faced in ancestral Miocene/Pliocene/Pleistocene environments. There is a far more interesting and important evolutionary story to be told.

Steven Mithen



Post: 2 Submitted: 1-13-97
From: Steven Quartz

Does Steven Pinker really think the Internet isn't catching on because the "mind evolved to deal with physical objects?" If the mind is so wedded to physical objects how did the phone line that makes faxes possible ever replace the written letter as a primary medium of communication? It would be hard to think of a technology that has been more eagerly (and in many cases uncritically) adopted than the Internet-just ask the U.S. Postal Service, who is losing billions every year to e-mail, or the original stockholders of NetScape.

To me this sort of "the mind was designed to (fill in your favorite behavior)..." argument typifies the vague half-truths of evolutionary psychology. It is an old point, but still timely: Looking just to the constraints imposed by natural selection wildly underdetermines the diversity of human behaviors seen across the spectrum of human cultures (to say nothing of the possible range of human abilities). The mind didn't evolve to write books about its own evolution, ponder the paradoxes of set theory, mow the lawn every week, or waste time surfing the net, but there it is. The Internet, remote access technologies, and new forms of computer-mediated knowledge representation and manipulation will be deeply transforming because the mind isn't limited to life as our Pleistocene ancestors knew it. The mind is constrained by natural selection, not shackled by it.

By looking simply at the constraints natural selection imposes on the mind's capacities, evolutionary psychology invites us to bite into a false (and vampire-like) dichotomy: Is it learned, or is it innate? When we look inside the brain what we find is something far more interesting, a self-organizing system in which structure is generated from the interaction between a structured world (which we ourselves structure with culture) and a brain with its own intrinsic constraints. The really interesting research program isn't to suppose everything has to be built into the brain via organs of computation (incidentally, contemporary brain science provides no evidence for innate organs of computations). The interesting problem is to decipher the principles of this interaction, the nature of the biological constraints, and how that interaction can produce the extraordinarily diverse behaviors and cognitive capacities we see all around us. Terry Sejnowski and I have suggested (http://www.cogsci.soton.ac.uk/bbs/Archive/bbs.quartz.html is an online version of a forthcoming article in Behavioral and Brain Sciences) that the principles of this interaction are rich enough to minimize the amount of domain-specific knowledge that must be built-in — that the computational machinery is built by this interaction.

Understanding the interaction between brain and world that builds the mind will take the perspective of all the human sciences. With a maturing brain science, a new generation of computer modeling, and cognitive neuroscience's naturalistic approach, it would seem the final pieces are falling into place for such a collaborative project. But first we need to move beyond the old dichotomies.

One more impression of the Pinker interview. Another one of evolutionary psychology's gambits is the zero-sum game metaphor, one Pinker uses in discussing happiness: If I'm happy it's because someone else isn't. The fact is, most people are happy-80% of Americans describe themselves as happy. Objective life circumstances play little role in determining who is happy and who isn't-the vast majority are happy despite being poor, downtrodden, or even severely handicapped physically (a good review of the literature is Myers and Diener, "Who is Happy?" Psychological Science, Jan 1995). Not everything need be a scarce resource in a Hobbes-like struggle of all against all.



Post: 3 Submitted: 1-13-97
From: Nicholas Humphrey

Steven Pinker is right about so much and argues the case so well, that if he ever has a bad idea it stands out like a sore thumb. I think there is one really bad idea in his discussion with JB. This is the suggestion that when a man threatens to kill a potentially unfaithful mate, he had better be prepared to carry out the threat even if it would hurt him to do it, or else the threat won't be credible.

It's true of course that he wants his threat to be believed, and it probably won't be believed unless other men have in fact carried out such threats in the past - so that his mate has reason to believe that such semi-suicidal acts of revenge are in general "typical" of male behavior. But this does not mean that he himself would stand to gain anything if , when his threat failed to deter her, he did in fact behave as a typical male. Clearly, in such circumstances he would in fact do better to "cheat" on the sexual stereotype - and walk away.

It's the old issue of a group policy that potentially requires self-sacrifice being liable to invasion by an individual free-rider. (There was a similar paradox with the cold war policy of Mutually Assured Destruction - but that's another story)



Post: 4 Submitted: 1-14-97
From: Patricia S. Churchland

I have a small challenge for Steven Pinker. Could he actually name a real living person (i.e. nonstrawman) who thinks that we can understand cognition by looking only at the brain itself?

Cheers,

Pat



Post: 5 Submitted: 1-17-97
From: Sandra Blakeslee

I would like Steve to tell us more about what he means by a "mental organ." It seems to be a metaphor more than a biological reality. Is there any evidence that mental "organs" exist? How are they organized? What is known about their wiring, physiology, dynamics, etc. Or this is a made-up term?



Post: 6 Submitted: 1-23-97
From: Steven Pinker

I thank Steven Mithen, Steven Quartz, Nicholas Humphrey, And Patricia Churchland for their thought-provoking comments. The oral interview format forced me to simplify and abbreviate arguments, and I apologize for those cases in which my points didn't come through clearly.

1. Steven Mithen asks how an evolutionary-psychology or reverse-engineering approach would shed light on "mega-quirks" like religion and racism, which have such profound effects on human affairs but do not seem particularly well engineered. Excellent questions, which I deal with at length in How the Mind Works.

First, a few points on the general theory. I *don't* believe that human behavior is adaptive or well engineered in an everyday sense of the words, for three reasons: (i) The criterion for "good engineering" in the evolutionary sense is replication of genes. That often diverges from other criteria that we think of as "adaptive" in nonbiological contexts: happiness, moral values, harmony, efficiency of the group. (ii) The brain is engineered for successful outcomes in the environment in which we spent most of our evolutionary history, and may lead to wildly non adaptive behavior in the recent, topsy-turvy world of civilizations. (iii) Like all biological structures, some features of the brain are adaptations, others are the inevitable nonadpative by-products and spandrels of the adaptations. The challenge for psychology is to figure out which is which. (iv) Behavior didn't evolve; the mind (i.e., brain) did. Overt behavior is an outcome of intricate interactions among mental faculties and among other behaving human beings. The mind's structure is bound to be more orderly than actual behavior.

About religion itself: In HTMW, I rely on the anthropological literature to try to figure out why in all cultures, including ours, the so-called rational animal believes in things that are patently false, such as ghosts and spirits. It's a complicated question, one that I do not claim to answer, but here are some helpful ideas:

(a) The question "Is X adaptive?" must always be completed with "adaptive for whom?" One has to distinguish among parties with competing interests. It may not be adaptive for a typical person to believe in hocus-pocus, but it may be adaptive for a typical person to defer occasionally to experts, and it may be adaptive for "experts" to inflate their status by alluding to a world of great power and wonder reachable only through their services. Tribal shamans are flim-flam artists who supplement their practical knowledge (herbal medicine and such) with cheap stage magic, and enjoy great prestige and all its perquisites. Readers may make their own comparisons to Western religions.

(b) There are hints that religious beliefs are spandrels of cognitive faculties that in ordinary circumstances accomplish more mundane feats, such as figuring out how objects, plants, animals, and other people work. First, religious beliefs are recognized by their believers to be out of-the-ordinary, accompanied by a sense of awe and wonder. Second, they are minor modifications of ordinary cognitive categories (spirits, for example, have the standard inventory of human beliefs and desires that people impute to other people; the spirits are just stipulated to lack bodies or some physical property of bodies). Third, religious beliefs are typically invoked when a person is in desperate straits and the usual remedies for success in the physical world have failed. "Religion is everywhere a recipe for success," said Ruth Benedict; people pray (or in our society, call the Psychic Hotline) for success in love, competition, finance, and overcoming illness.

(c) The evidence that makes religious beliefs so obviously wrong to us scientists is recent, and, lamentably arcane even in our society. And the phenomena that most directly inspire spiritual beliefs worldwide — dreams, death, altered states — involve consciousness, which, pace Dan Dennett, even some contemporary scientists feel has not yet been explained.

2. Racism (more generally, ethnocentrism, for most hatred worldwide is within-race). Mithen writes, "Tell ... oppressed people that the minds of their oppressors are organs of extreme perfection (to either ancestral or modern conditions) and I suspect that they will hasten to disagree." See my general point (i) above. Mithen substitutes our ordinary sense of perfection (moral rightness, personal happiness, societal harmony and efficiency) for the one that is relevant to a scientific understanding of the brain, namely gene replication. Ethnocentrism may or may not be biologically well engineered, but the misery and tragedy it causes is irrelevant to that particular question (compare: "Tell the family of a murder victim that a gun is a well-engineered machine." or: "Tell the zebra that a lion is an organism of extreme perfection." It all depends on which criteria for "well-engineered" and "perfection" you have in mind.)

Now, could collective aggression against conspecifics be adaptive in the narrow, biological sense? It has evolved several times, so it's at least possible. In human warfare before civilization, villages raid each other to abduct women or deter abductions, and Napoleon Chagnon and Laura Betzig have gathered extensive data from many sources showing that until recent conditions obtained aggressive men were reproductively more successful. (As Betzig points out, the entry in the Guinness Book of World Records for the human with the most children — close to a thousand — belongs to a man named Moulay Ismail the Bloodthirsty.) Such evidence doesn't settle the question (and it certainly doesn't render ethnic warfare "natural" in the sense of "good" or "inevitable"), but it shows that morally repugnant mega-quirks are not necessarily design flaws in the narrow biological sense.

2. Steven Quartz asks whether I really think the Internet isn't catching on because the "mind evolved to deal with physical objects," pointing to the telephone. The telephone cunningly simulates a different kind of human interaction with the world, oral conversation, so it doesn't need to tap object cognition. And I would, indeed, cite the recent success of the Web as an example of the overall point. Web-browsers don't literally deliver much more information than the old text-based Internet interfaces (telnet, ftp, gopher, etc.), but they are responsible for the explosion of Internet use outside the university. Why? Because they tap in to visual-spatial cognition, and better simulate physical interactions with the world like pressing buttons, turning pages, and traveling along paths through space. One of the biggest current efforts in the development of web interfaces is how to use graphic representations to give the user a better sense of currently confusing information such as document contents and web topology.

Quartz also points out, "Looking just to the constraints imposed by natural selection wildly underdetermines the diversity of human behaviors seen across the spectrum of human cultures (to say nothing of the possible range of human abilities). The mind didn't evolve to write books about its own evolution, ponder the paradoxes of set theory, mow the lawn every week, or waste time surfing the net, but there it is." I agree with the latter — see (i) to (iv) above, which explain why evolutionary thinking is not about constraints on behavior at all.

However, I do disagree with the following: "By looking simply at the constraints natural selection imposes on the mind's capacities, evolutionary psychology invites us to bite into a false .. dichotomy: Is it learned, or is it innate?" That dichotomy is indeed all too common (see, for example, the recent paper on language acquisition by Safran, et al., in Science, which frames its hypotheses in almost exactly those words). But it is evolutionary psychology that argues most strenuously that the dichotomy is incoherent (see, e.g., Tooby & Cosmides' The Psychological Foundations of Culture; Marler & Gould's paper Instincts to Learn; Gallistel's contribution to the Gazzaniga volume; Chapter 13 of my Language Instinct, and soon, HTMW).

More generally, I don't think that "constraints" are a particularly useful way of characterizing the mind, either in the human-potential sense of "Don't try to change blah-blah-blah, it's constrained by the genes and hence inevitable," or even in Quartz's framing of development as an interaction between a structured world and a constrained brain. I don't disagree outright that there is such an interaction, but think we can do better. The brain is not a list of "constraints" but a highly structured and adapted organ, which is designed to process information in clever ways both as it assembles itself in utero and when it guides the whole organism. As for whether "contemporary brain science provides no evidence for innate organs of computations" — wel l, so Quartz and Sejnowski argue, but other brain and cognitive scientists interpret the same evidence differently. That will have to be a discussion for another day.

On happiness: I'm confused by the criticism that "objective life circumstances play little role in determining who is happy and who isn't." That was precisely my point! Happiness, according to the research Quartz and I both cite, is determined in large part by how much better or worse off you are now compared with how you recently were, and how much better or worse off you are relative to members of a group you compare yourself to. (Note, by the way, that that's very different from Quartz's summary, "I'm happy because someone else isn't".) A huge literature in social psychology documents these statements, and they are better explained by thinking of happiness as part of a striving-calibrator than as our everyday concept of just desserts.

3. Nicholas Humphrey disagrees with the theory (which I borrowed from several economists and game theorists) that irrational passion may have evolved to make our threats, promises, and bargaining positions more credible. He notes that a vengeful estranged husband, for example, would not "stand to gain anything if, when his threat failed to deter her, he did in fact behave as a typical male. Clearly, in such circumstances he would in fact do better to `cheat' on the sexual stereotype - and walk away." First, the theory is not about people's reactions to stereotypes or group precedents; it is about their reaction to other individuals. Not, "Does a typical male kill his estranged wife?" but "Is this guy crazy enough to come after me?" Indeed, it is Humphrey himself who deserves the credit for alerting us all to the highly developed Machiavellian intuitive psychology in the human mind. And, there lies the problem in Humphreys' cricitism here — of course, the man would do better to walk away, but that's exactly what the wife would predict if she had reason to believe he was a passionless cost-benefit appraiser — in turn allowing her to call his bluff. Only if some part of him was *irrational*, in this specific sense of being willing to carry through a threat regardless of its costs, would the threats be effective.

A corollory, by the way, is that "What does X stand to gain by carrying out his threat?" is the wrong question. It enters the story too late — after the target has defied the threat — and presupposes that at that moment X is calculating the costs and benefits of alternative acts, which is precisely what is at issue. The right question is, "What do X's genes have to gain, over the long term, by wiring X up so that X is compelled to carry out his or her threats?" And the answer is, deterring adversaries. Deterrence is a proactive notion; it always looks pointless post hoc. In cases of brinkmanship and bluff-calling, it may have terrible costs, but its average benefit is in all the examples of brinkmanship and bluff-calling that it prevents from ever taking place. (See also my general point (i) at the beginning.) Humphreys' analogy of the paradox of Mutually Assured Destruction is apt, as is the moral paradox of criminal deterrence ("Hanging the murderer won't bring the victim back to life"). I think human passion is paradoxical in precisely those ways.

4. Patricia Churchland challenges me to name a nonstraw person who thinks that we can understand cognition by looking only at the brain. I would begin with 90% of the membership of the Society of Neuroscience. The ignorance of psychology and cognitive science among neuroscientists was considered a serious enough problem by a recent executive of the society that she convened a strategy session at the annual meeting to brainstorm about what to do about it. And it has real consequences for how research is conducted. Two examples are neuroimaging studies of language, which until recently were carried out as if the topic had never before been studied, and the search for the neural basis of learning, which has been equated with the search for a neural version of the associative bond, a notion considered antique within ethology, animal learning, and most of cognitive science.

As for prominent individual spokespeople: admittedly, my remark was not carefully worded, and no one would let himself be characterized in exactly that way. But there are real people with whom I disagree on whether our understanding of the brain must be couched exclusively in neurophysiological terms (and perhaps that is a better statement of what is at issue). For example:

"I claim that the entire structure on which the cognitivist enterprise is based is incoherent and not borne out by the facts. ... [It is an egregious category mistake to think that] the whole enterprise can proceed by studying behavior, mental performance and competence, and language under the assumptions of functionalism without FIRST understanding the underlying biology." [emphasis added]

— Gerald Edelman: Bright Air, Brilliant Fire.

"There are brute, blind neurophysiological processes and there is consciousness, but there is nothing else. .... [There is no] rule following, no mental information processing, no unconscious inferences, no mental models, no primal sketches, no 2 1/2-D images, no three-dimensional descriptions, no language of thought and no universal grammar." — John Searle: Consciousness, explanatory inversion, and cognitive science, in Behavioral and Brain Sciences.

The Emperor's New Mind — title of a book by Roger Penrose attacking the idea that thinking can be understood as a form of computation.

Incidentally, my remark about people who want to look only at the brain was not meant to include Churchland herself (though I am sure we do disagree about many things). I loved the title of her excellent book with Sejnowski, The Computational Brain — and point out that Searle, Penrose, and, if I read him correctly, Edelman, deny that the brain does computation.

Thanks again to the commentators for allowing me to clarify my remarks in the interview.



Post: 7 Submitted: 1-31-97
From: Nicholas Humphrey

To: Steven Pinker

Steven Pinker says "the theory [of male revenge killing of wives] is not about people's reactions to stereotypes or group precedents; it is about their reaction to other individuals. Not, 'Does a typical male kill his estranged wife?' but 'Is this guy crazy enough to come after me? '".

However I don't think the two issues are so easily separable. The question has to be: how could a wife possibly get to know that her husband is so crazy? Presumably it isn't, as it were, "transparent": she cannot actually see the wiring in his brain that might be responsible for launching automatic unstoppable revenge. So the best she can do is to infer it on the basis of indirect clues. But what could these clues possibly be, except either (i) evidence of this individual male having gone crazy in the past and killed a previous wife, or (ii) evidence of other males having killed their wives in the past. In neither case, however, could such evidence tell her for certain how her particular male will act on the next occasion. And so the possibility must still be there that, if and when a new occasion for revenge does arise, the male will decide not to follow the precedent that has been set (either by himself or his sex in general). The wife has therefore to rely on what she knows about typical male behavior. But in this case the male will indeed do better if he cheats on the stereotype and, instead of taking revenge, walks away.

The crucial difference between this example and other possible examples of effective deterrence lies precisely in the non-transparency of the system that brings about revenge. Deterrence in general can only work when there actually are public guarantees that revenge will follow automatically, come what may. This could be the case, for example, if the revenge mechanism were in fact open to inspection, so that the potential victim can be in no doubt about what will happen. During the Cold War, certain deterrence strategists suggested that each side should allow the other to inspect its arrangements for nuclear retaliation for just this reason. But the problem is that this kind of guarantee can never be provided when the mechanism is hidden inside the brain and cannot in principle be open to inspection from outside.

But Steven Pinker acknowledges that this isn't really his field (he borrowed the example from games theorists) - and nor, I hasten to say, is it mine. Would anyone else like to join in? How about opening up this and the other issues Pinker raised to a general discussion.-

Nicholas Humphrey



Post: 8 Submitted: 1-31-97
From: Rick Potts

Every structure, every behavior, every characteristic of an organism has a history. The human mind is no exception - as Steven Pinker notes, an evolutionary history shaped by (1) a long sequence of surrounding conditions and (2) novel changes in the brain's genetic underpinnings, which happened to give certain hominids a reproductive and survival advantage over others. This leads to Pinker's emphasis on "reverse-engineering" - an analytical metaphor on which his study of mind and the field of evolutionary psychology, in general, are based.

If you reverse-engineered the human shoulder, you would find (in comparison with most other primates) that it is designed well for brachiation. Swinging in the trees is what the human shoulder is about (seen by the upward angle of the glenoid fossa, the mechanical advantage of the "rotator cuff" muscles, the broad thorax to which it is attached, etc.). If you reverse-engineered the human foot, you would find a rigid paddle designed to bear the body's weight on the ground during striding. No tree-living in that creature's history, surely!

My point: Reverse engineering, as it relies only on present observations, inadequately distinguishes very old functions (so-called primitive e features shared with other organisms) from the unique operations of the organism we're interested in (so-called derived features that are, in a discussion of the human mind, particular to Homo sapiens).

As my example illustrates, our species is a complex mixture of structures and activities (including mental activities) that pertain to unique strategies of survival and reproductive success, and others that echo a more distant past. The latter may or may not still be engaged in human adaptation. To continue my analogy, a controlled laboratory test (a method so effectively carried out by evolutionary psychologists) would show that young humans can hang and swing by their arms (just as shoulder design indicates), and that they even enjoy these activities; still, arm hanging has little to do with human foraging, basic moving about, or survival - I.e., how the human arm now works.

The analysis of "how the mind works" that Pinker suggests has strong possibilities for confounding different segments of our evolutionary past. Human-nonhuman comparisons are a way around this problem, and I look forward to a healthy dose of the comparative method in Pinker's new book. At the same time, evolutionary psychologists (and Pinker, too, given his own phrasing) adopt a monolithic and mistaken view of "the environment" of human evolution. (Brevity is risky here; nevertheless...) Their goal is to reconstruct that "environment" (sometimes called the "environment of evolutionary adaptedness," or EEA) by looking at present behavior and mental function. They then consider this to be an evolutionary "understanding" of human functioning. Well, what environment are they talking about?

We all agree that certain human decisions and brain-mediated actions are shared with many other mammals. In that case, we're talking about "an environment" beginning perhaps 200 million years ago, much of which represented ecological, social, and genomal conditions that were quite different from those experienced specifically by hominids over the last 5 million years. If we seek to understand uniquely human mental functions, then the environments of the past 5 myr are far more important to consider. And if we want to guess how modern human minds differed from those of earlier hominids, then only the past 1 million, or even the last few hundred thousand years, are relevant.

Analysts who employ reverse engineering keep referring to "the environment" but never really examine past environments or much about past hominids. According to evolutionary psychologists, the EEA is somehow encoded in the modern brain and mental functioning. Which environment? What time are they talking about? Failure to answer these questions leads, potentially, to misunderstanding the evolution and current functions of the human mind.

As I've argued (Humanity's Descent: The Consequences of Ecological Instability, Wm. Morrow, N.Y., 1996; and Science, vol.273, pp.922-923, 1996), the setting that shaped human adaptations over the past 5 million years primarily involved episodic fluctuation between habitat extremes. Resource distributions and abundances were repeatedly disrupted. As this happened, the factors that influenced natural selection were also greatly recast - affecting foraging, social life, mating, and competitive settings. Pleistocene environments, which involved threshold-type oscillations, differed in many ways from, say, Eocene or Oligocene environments.

So, to the extent that social/individual functioning (e.g., mental problem solving) is tied to habitat and resources, the answer to "which environment?" is that it depends! Brain-mediated functions shared by all higher primates originated in one set of adaptive settings. Functions unique to hominids evolved in quite different surroundings. The latter involved a dramatic sequence of diverse environments, which posed episodic and unpredictable adaptive challenges to hominids - not the same challenge over and over. Adaptive evolution in the genus Homo, I've proposed, responded mainly to disparities in selective conditions - in contrast with the uniformities or regularities of natural selection emphasized by evolutionary psychologists. If adaptive evolution in some organisms, notably later hominids, was a response to many diverse selective regimes, it rather dramatically alters the way we think about evolution and present function. At the very least, it means that, for some key aspects of human mentality, the monolithic notion of "the environment" or EEA, which is so important to the lingo and understandings of evolutionary psychologists, should be relegated to the dust bin.

In sum, I question exactly what the testing of present mental structure shows us about the evolution of the human mind. As the shoulder-foot comparison implies, design analysis tells us about present function but may confound early history with functions unique to human adaptation. I also question whether "presentist" analyses of mind indicate "the environment" in which the mind evolved. Reverse engineering is usually an analysis without past context. Natural selection ends up lacking time and place. It does not necessarily discern the crucial distinction between shared/primitive and unique/derived regimes of adaptation for the human species. To the extent that language is involved in organizing human mental function, social and ecological environments earlier than 1 or 2 million years ago may be irrelevant to understanding how the unique aspects of living human minds actually work. Natural selection, we've all learned, occurs within local settings. A "presentist" analysis of mental structure, ironically, lacks the time place context so essential to the past evolutionary effects of natural selection.

Paleoanthropologists are beginning to build a better bridge to environmental sciences. Past habitats surely affected past and present adaptive strategies. In thinking about hominids, however, evolutionary psychologists have relied too much on arm-chair assumptions about how natural selection must work, without studying the past. It is exciting to think about building a better bridge to evolutionary psychologists, and how this would unify the study of human adaptation and evolutionary history.

Rick Potts

 


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