And the Smarties test provides us with a refutation of the suggestion.
Children whose concept of false belief is not yet developed have diYculty
recognising and recalling their own false beliefs. So children must some-
how be revising their simple folk-psychological theory to include possible
false belief, but without yet having any conception of false belief, and so
without yet having access to their own false beliefs, either. This seems a
diYcult theorising task indeed!
This point may be worth elaborating further, since it has implications
for philosophy of science. It is very diYcult to understand how mind-
reading could be a product of quasi-scientiWc theorising, given that chil-
dren pre-four lack any concept of false belief. For what can motivate you
to revise a theory in the face of recalcitrant data, if you cannot yet entertain
the thought that the data suggest thatyour theory is false? In other words,
we would argue quite generally that theory-of-mind development cannot
be explained in terms of quasi-scientiWc theorising, because scientiWc theor-
ising would be entirely impossible without mind-reading ability. This is
clearly a theme which deserves treatment in its own right. For the time
being we refer readers to some of Fodor’s suggestive thoughts on the
connection between experiments and the management of beliefs (1994).
So there is a strong case for the view that mind-reading ability is innate,
rather than being the product of theorising. This has now been dramati-
cally conWrmed in a twin-study undertaken by Hughes and Cutting of the
London Institute of Psychiatry (personal communication). They perfor-
med a whole battery of mind-reading tests on over 100 three-year-old
twins, looking at diVerences in performance amongst monozygotic (‘ident-
ical’) twins, who share the same genes, as opposed to diVerences in the
performance of dizygotic (‘fraternal’) twins, who have just 50 per cent of
their genes in common. It turns out that two-thirds of children’s variance
on mind-reading tests is attributable to genetic factors, with only one third
being attributable to environmental factors. Yet the genes in question turn
out to be largely independent of those involved in the acquisition of other
sorts of ability, such as language.
There is one piece of developmental evidence which might be thought to
suggest that mind-reading ability isnotinnate: it is known that children
with more siblings tend to pass the false-belief test earlier (Perneret al.,
1994). But we suggest that this is likely to be an instance of the general
developmental principle that variation in opportunities to exercise a ca-
pacity can accelerate or retard the rate at which that capacity develops in a
child. Co-variation of that sort is to be expected in development which is
fundamentally a matter ofgrowth, just as much as in cases in which
children are learning from the input they receive. Moreover (as we noted in
section 1.1 above) although some people may also be tempted to claim that
94 Mind-reading