Bearers of such genes would tend to have more offspring than non-
bearers and some of their offspring would carry these genes too.
Now problems of adaptive significance come in very different
shapes. For instance, you must be able to detect whether there are
agents around or just mechanical events—whether the movement in
the tree was caused by the wind or by an animal lurking up there. But
you must also keep track of who interacted with you, when and with
what results, otherwise stable cooperation would be impossible—and
this requires special memory-stores and adequate face-recognition.
These two problems are very different, and it is very dubious that a
single system could handle both tasks. And this is only the beginning [117]
of a very long list of specific adaptive problems. Detecting what makes
some people reliable for cooperation is not the same as detecting what
makes potential sexual partners attractive, which is not the same as
evaluating whether a particular food is poisonous or not. It is not just
that these problems are different in their subject matter but that they
require different ways of handling information. To be efficient in
interaction with people you must recall what each person did and infer
their motivation in each case; but if you are dealing with animals, you
can consider all members of a species more or less similar.
These considerations led a number of evolutionary biologists to
consider that during evolution an organ as complex as the human
brain would probably accumulate lots and lots of such specialized sub-
systems, thereby making the system as a whole bigger and smarter.
Indeed, the idea was that being smart consists in having lots of special-
ized systems that handle only one problem, rather than just a larger,
general-purpose intelligence. This would make sense because a large
system would be bogged down by irrelevant details. If for instance our
face-recognition system kept specific files for each individual animal
we ever encountered, this would both waste resources and make us
rather sluggish when a quick response is needed. The relevant
response to the presence of a giraffe or a tiger depends on the species,
not on the individual. So there was an evolutionary story to suggest
ever-increasing specialization as the origin of complex cognitive
capacities like those of higher primates and humans. In this view,
smarter species got smarter by having more instincts than other
species, not fewer. But this remained a conjecture.^18
The situation changed when, independently from these biological
conjectures, developmental psychologists and neuropsychologists
began to demonstrate more and more specialized inference systems (as
THEKIND OF MIND ITTAKES