from less powerful machines which were organised along modular lines –
rather, one would expect these modular systems to have been altered,
added to, and interconnected in novel ways (Barkowet al., 1992). So even
before looking at more direct evidence, modularity is what we should
expect.
2 The case for nativism
The central argument against empiricist theories of learning is grounded in
the problem of acquisition– also referred to asPlato’s problemorthe
poverty of the stimulus. The problem is: how do children learnso much,so
quickly, on the basis ofsuch limited and inadequate data, if all that human
children can bring to the task are general perceptual and cognitive abil-
ities? Chomsky originally urged this argument in the case of acquisition of
one’s native language, but it applies with equal force to certain other
domains (see chapter 4 on the development of our ‘mind-reading’ capaci-
ties). How forceful the argument is in any particular domain depends upon
the facts – how much has to be known, how quickly the child develops a
competence which requires that knowledge, and what relevant experiential
input is available during the process of development.
Note that while we are committed to a general nativist research pro-
gramme in psychology, we areempiricists about our nativism. Thus: there
are grounds of coherence with general evolutionary theory for supposing
that some of our psychological capacities deploy genetically inherited
mechanisms; there are some cognitive domains in which the evidence for
such inherited psychological mechanisms is extremely strong; but it re-
mains to be seen what other areas of cognition depend upon genetic
pre-programming. We are not denying that there is such a thing as learning
from experience. One of the things to be learnt through the vicarious
experience of psychological research is where we do and where we do not
learn from experience!
As noted above, the Chomskian case concerning development is some-
times called ‘the Poverty of the Stimulus’ argument. However, that seems
to us a misnomer which invites doubts about the strength of the reason-
ing. Are the data available to the learner really so inadequate? Have the
Chomskians exaggerated the competence which is acquired? A further
worry might be prompted by a parallel with speciation and environmental
inXuences. A favourite argument of critics of evolutionary theory has
been that environmental factors are neither strong nor speciWc enough to
shape evolutionary development – that, in eVect, there has beena poverty
of the environmental stimulus. Yet Darwinians have never been much
moved by such arguments, holding that they simply underestimate the
52 Modularity and nativism