of complex social signals. And it also seems likely to engage in surprisingly
complex computations using beliefs as inputs – for example, there is the
startlingWnding by Baker and Bellis (1989), that the extent of sperm-
production in men is proportional, not to the time elapsed since the last
ejaculation (as might be expected), but rather to the amount of elapsed
time for which the man has been physically separated from his partner
(time during which she may have had other opportunities for mating), as
predicted by sperm-competition theory.
We have also included inWgure 3.3 a desire-generating module marked
‘status’. It is a remarkable fact about human beings – which is not re-
marked upon often enough in cognitive science, it seems to us – that
human desires can encompass an astonishingly wide and varied set of
objects, states and events. Something must act to generate such diversity,
since it is mysterious how mere exposure to culture alone could produce a
new set of desires. One plausible proposal is that we have a dedicated
system which monitors others’ attitudes to oneself, and computes which
objects or events are likely to improve one’s social status. Any such module
would have to take beliefs as inputs, plainly – such as the belief, ‘People
who drive fast cars are admired’, or the belief, ‘People who are kind to
animals are liked’. And it seems likely that one sub-goal in these modular
computations would beto stand out from the crowd– hence giving us at
least the beginnings of an explanation of why human desires tend to
proliferate and diversify.
6 Conclusion
In this chapter we have presented the arguments for nativism, and for
modular functional organisation of cognition, which are interlinked. We
have also argued that modularity is probably not just conWned to input
and output systems, but characterises central cognition as well (belief-
Wxation of various kinds, practical reasoning, desire-generation, and so
on). The resulting picture of the mind does not sit entirely easily with our
conception of ourselves as integrated and unitary subjects of thought and
experience. But it is at least consistent with the central commitments of
folk psychology; and it does at least hold out the prospect of future
scientiWc understanding. We shall return in chapters 8 and 9 to consider
whether anything of our supposed cognitive unity can be preserved within
a scientiWc account of consciousness.
Conclusion 75