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

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)

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.