Darwin's Dangerous Idea - Evolution and the Meaning of Life

488 ON THE ORIGIN OF MORALITY
factors from cultural commonalities, and for the same reason. But, although
Wilson has sometimes noted this problem, at other times he forgets:
The similarities between the early civilizations of Egypt, Mesopotamia,
India, China, Mexico, and Central and South America in these major features
are remarkably close. They cannot be explained away as the products
of chance or cultural cross-fertilization. [Wilson 1978, p. 89]
We need to look at each remarkable similarity in turn, to see if any of them
needs a genetic explanation, for, in addition to cultural cross-fertilization
(cultural descent) and chance, there is the possibility of reinvention. There
may be specific genetic factors operating in many or all these similarities,
but, as Darwin stressed, the best evidence will always be idiosyncrasies—
quirky homologies—and no-longer-rational survivals. The most compelling
cases of this sort are currently being uncovered in the marriage of sociobiology
and cognitive psychology recently going by the name of evolutionary
psychology (Barkow, Cosmides, and Tooby 1992 ). Highlighting a single case
will provide a useful contrast between good and bad uses of Darwinian
thinking in the study of human nature, and clarify the position on rationality
(or just nonstupidity) just presented.
How logical are we human beings? In some regards very logical, it seems,
and in others embarrassingly weak. In 1969, the psychologist Peter Wason
devised a simple test that bright people—college students, for instance—do
rather badly on. You may try it yourself. Here are four cards, some letterside-up,
and some number-side-up. Each card has a numeral on one side and
a letter on the other:
Your task is to see whether in this case the following rule has any exceptions:
If a card has a "D" on one side, it has a "3" on the other side. Now, which
cards do you need to turn over in order to discover if this is true? Sad to say,
fewer than half of students in most such experiments get the right answer.
Did you? The correct answer is much more obvious if we shift the content
(but not the structure) of the problem very slightly. You are the bouncer in a
bar, and your job depends on not letting any underage (under twenty-one)
customers drink beer. The cards have information about age on one side, and
what the patron is drinking on the other. Which cards do you need to turn
over?
Sociobiology: Good and Bad Good and Evil 489
The first and the last, obviously, the same as in the first problem. Why is one
setting so much easier than the other? Perhaps, you may think, it is the
abstractness of the first, the concreteness of the second, or the familiarity of
the second, or the fact that the second involves a conventional rule, not a
regularity of nature. Literally hundreds of Wason card-sorting tests have been
administered to subjects, in hundreds of variations, testing these and other
hypotheses. The performance of subjects on the tests varies widely,
depending on the details of the particular test and its circumstances, but a
survey of the results leaves no doubt at all that there are settings that are hard
for almost all groups of subjects, and others that are easy for the same
subjects. But a riddle remained, reminiscent of the riddle of the two black
boxes: what exactly was it about the hard cases that made them hard—or (a
better question) what was it about the easy cases that made them easy?
Cosmides and Tooby (e.g., Barkow, Cosmides, and Tooby 1992, ch. 2 ) came
up with an evolutionary hypothesis, and it is hard to imagine this particular
idea occurring to anyone who wasn't acutely aware of the possibilities of
Darwinian thinking: the easy cases are all cases that are readily interpreted as
tasks of patrolling a social contract, or, in other words, cheater detection.
Cosmides and Tooby seem to have uncovered a fossil of our Nietzschean
past! Framing the hypothesis is not yet proving it, of course, but one of the
important virtues of their hypothesis is that it is eminently testable, and has
so far stood up very well to a wide variety of attempts to refute it. Suppose it
is true; would it show that we can reason only about the things Mother
Nature wired us to reason about? Obviously not; it just shows why it is easier
(more "natural") for us to reason about some topics than others. We have
devised cultural artifacts (systems of formal logic, statistics, decision theory,
and so forth, taught in college courses) that expand our reasoning powers
many fold. Even the experts often neglect these specialized techniques,
however, and fall back on good old seat-of-the-pants reasoning, sometimes
with embarrassing results, as the Wason test shows. Independently of any
Darwinian hypotheses, we know that, except when people are particularly
self-conscious about using these heavy-duty reasoning techniques, they tend
to fall into cognitive illusions. Why are we susceptible to these illusions? The
evolutionary psychologist says: For the same reason we are susceptible to
optical illusions and other sensory illusions—we're built that way. Mother
Nature designed us to solve a certain set of problems posed by the
environments in which we evolved, and whenever a cut-rate solution
emerged—a bargain that would solve the most pressing problems pretty well,
even if it lacked generality—it tended to get installed.
Cosmides and Tooby call these modules "Darwinian algorithms"; they are
mechanisms just like the two-bitser, only fancier. We obviously don't get by
with just one such reasoning mechanism. Cosmides and Tooby have been
gathering evidence for other special-purpose algorithms, useful in thinking