Figure 3.3 Modular central-systems and folk-psychological statesconceptualised outputs of the perceptual systems; and some of which
generate desires(more on the latter in a moment).Note that – while wehave
not attempted to model this inWgure 3.3 – the belief-generating modules
maybe ableto takeasinputsthe outputsofothersuchmodules.In chapter 8
we shall consider a hypothesis concerning how this might take place,
according to which such inter-modular communication is mediated by
language.
We have represented inWgure 3.3 a variety of modular systems for
generating desires. Since desires do not, on the whole, loom large in this
book (nor in cognitive science generally), the existence and nature of such
modules may bear some additional comment here. The modular systems
which generate desires for food and drink will be at least partially respon-
sive to bodily states such as levels of blood-sugar, we presume. But they
may also take inputs from the various perceptual modules – think of how
the mere sight or smell of chocolate cake can make you feel hungry, say,
even if you are physically sated. And these modules may also eVect more
complex calculations, taking beliefs as inputs. Think, for example, of how
one tends to get hungrier when on a long journey, even though the energy
one expends while sitting in airport lounges is probably reduced from
normal. Although the evidence is merely anecdotal, one can easily think of
plausible evolutionary explanations for the existence of some such com-
putational hunger-generating mechanism. The sexual-desire module, too,
is likely to take a wide range of inputs, including sensings of internal bodily
states, tactile and visual experiences of various sorts, and representations
74 Modularity and nativism