Kluge: The Haphazard Construction of the Human Mind

If disorders extend from fault lines, they certainly move beyond them too. To the extent that genes clearly play a role in mental disorders, evolution is in some way — adaptively or otherwise — implicated. But our mental fault lines sometimes give rise to earthquakes, though at other times only tiny tremblors, scarcely felt. Evolution, however haphazard, can’t possibly be the whole story. Most common mental disorders seem to depend on a genetic component, shaped by evolution — but also on environmental causes that are not well understood. If one identical twin has, say, schizophrenia, the other one is considerably more likely than average to also have it, but the so- called “concordance” percentage, the chance that one twin will have the disorder if the other does, is only about 50 percent. For that reason alone it would clearly be overreaching to ascribe every aspect of mental illness to the idiosyncrasies of evolution.

But at the same time, it seems safe to say that no intelligent and compassionate designer would have built the human mind to be quite as vulnerable as it is. Our mental fragility provides yet another reason to doubt that we are the product of deliberate design rather than chance and evolution.

Which brings us to one last question, perhaps the most important of all: if the mind is a kluge, is there anything can we do about it?

8. TRUE WISDOM

God grant me the serenity to accept the things I cannot change, courage to change the things I can, and wisdom to know the difference.

— REINHOLD NIEBUHR

To know that one knows what one knows, and to know that one doesn’t know what one doesn’t know, there lies true wisdom.

— CONFUCIUS

HUMAN BEINGS HAVE INTELLECTUAL skills of unparalleled power. We can talk, we can reason, we can dance, we can sing. We can debate politics and justice; we can work for the betterment not just of ourselves but our species. We can learn calculus and physics, we can invent, educate, and wax poetic. No other species comes close.

But not every advance has been to the good. The machinery of language and deliberative reason has led to enormous cultural and technological advances, but our brain, which developed over a billion years of pre-hominid ancestry, hasn’t caught up. The bulk of our genetic material evolved before there was language, before there was explicit reasoning, and before creatures like us even existed. Plenty of rough spots remain.

In this book, we’ve discussed several bugs in our cognitive makeup: confirmation bias, mental contamination, anchoring, framing, inadequate self-control, the ruminative cycle, the focusing illusion, motivated reasoning, and false memory, not to mention absentmindedness, an ambiguous linguistic system, and vulnerability to mental disorders. Our memory, contextually driven as it is, is ill suited to many of the demands of modern life, and our self-control systems are almost hopelessly split. Our ancestral mechanisms were shaped in a different world, and our more modern deliberative mechanisms can’t shake the influence of that past. In every domain we have considered, from memory to belief, choice, language, and pleasure, we have seen that a mind built largely through the progressive overlay of technologies is far from perfect. None of these aspects of human psychology would be expected from an intelligent designer; instead, the only reasonable way to interpret them is as relics, leftovers of evolution.

In a sense, the argument I have presented here is part of a long tradition. Gould’s notion of remnants of history, a key inspiration for this book, goes back to Darwin, who started his legendary work The Descent of Man with a list of a dozen “useless, or nearly useless” features — body hair, wisdom teeth, the vestigial tail bone known as the coccyx. Such quirks of nature were essential to Darwin’s argument.

Yet imperfections of the mind have rarely been discussed in the context of evolution. Why should that be? My guess is that there are at least two reasons. The first, plain and simple, is that many of us just don’t want human cognition to turn out to be less than perfect, either because it would be at odds with our beliefs (or fondest desires) or because it leads to a picture of humankind that we find unattractive. The latter factor arises with special force in scientific fields that try to characterize human behavior; the more we stubbornly deviate from rationality, the harder it is for mathematicians and economists to capture our choices in neat sets of equations.

A second factor may stem from the almost mystifying popularity of creationism, and its recent variant, intelligent design. Few theories are as well supported by evidence as the theory of evolution, yet a large portion of the general public refuses to accept it. To any scientist familiar with the facts — ranging from those garnered through the painstaking day-to-day studies of evolution in the contemporary Galapagos Islands (described in Jonathan Weiner’s wonderful book The Beak of the Finch) to the details of molecular change emerging from the raft of recently completed genomes — this continued resistance to evolution seems absurd.[54] Since so much of it seems to come from people who have trouble accepting the notion that well-organized structure could have emerged without forethought, scientists often feel compelled to emphasize evolution’s high points — the cases of well-organized structure that emerged through sheer chance.

Such emphasis has led to a great understanding of how a blind process like evolution can produce systems of tremendous beauty — but at the expense of an equally impassioned exploration of the illuminating power of imperfection. While there is nothing inherently wrong in examining nature’s greatest hits, one can’t possibly get a complete and balanced picture by looking only at the highlights.

The value of imperfections extends far beyond simple balance, however. Scientifically, every kluge contains a clue to our past; wherever there is a cumbersome solution, there is insight into how nature layered our brain together; it is no exaggeration to say that the history of evolution is a history of overlaid technologies, and kluges help expose the seams.

Every kluge also underscores what is fundamentally wrongheaded about creationism: the presumption that we are the product of an all-seeing entity. Creationists may hold on to the bitter end, but imperfection (unlike perfection) beggars the imagination. It’s one thing to imagine an all-knowing engineer designing a perfect eyeball, another to imagine that engineer slacking off and building a half-baked spine.

There’s a practical side too: investigations into human idiosyncrasy can provide a great deal of useful insight into the human condition; as they say in Alcoholics Anonymous, recognition is the first step. The more we can understand our clumsy nature, the more we can do something about it.

When we look at imperfections as a source of insight, the first thing to realize is that not every imperfection is worth fixing. I’ve long since come to terms with the fact that my calculator is better than I am at solving square roots, and I see little point in cheering for Garry Kasparov over his computer opponent, Deep Blue, in the world chess championships. If computers can’t beat us now at chess and Trivial Pursuit, they will someday soon. John Henry’s fin-de-siecle Race Against the Machine was noble but, in hindsight, a lost cause. In many ways machines have (or eventually will have) the edge, and we might as well accept it. The German chemist Ernst Fischer mused that “as machines become more and more efficient and perfect, so it will become clear that imperfection is the greatness of man.” A creature designed by an engineer might never know love, never enjoy art, never see the point of poetry. From the perspective of brute rationality, time spent making and appreciating art is time that could be “better” spent gathering nuts for winter. From my perspective, the arts are part of the joy of human existence. By all means, let us make poetry out of ambiguity, song and literature out of emotion and irrationality.

That said, not every quirk of human cognition ought to be celebrated. Poetry is good, but stereotyping, egocentrism, and our species-wide vulnerability to paranoia and depression are not. To accept everything that is inherent to our biological makeup would be to commit a version of the “naturalistic fallacy,” confusing what is natural with what is good. The trick, obviously, is to sort through our cognitive idiosyncrasies and decide which are worth addressing and which are worth letting go (or even