Adapted Mind (Barkow et al. (1992), p.10), there are two basic research strategies
available to the evolutionary psychologist:
1. Explanatory evolutionary psychology: This general methodology argues from
the present to the past. Present observations direct us to the hypothesis of an
adaptive problem from our ancestral past. The problem is then used to explain the
existence of the present observations. As examples of the explanatory meth-
odology Cosmides, Tooby and Barkow cite Boulton and Smith (1992), Neese
and Lloyd (1992), Profet (1992), Shepard (1992).
2. Predictive evolutionary psychology: This general methodology argues from the
past to the present. A hypothesis about the existence of past adaptive problems
points us toward likely present observations. As examples of the predictive
method Cosmides, Tooby and Barkow cite Buss (1992), Cosmides and Tooby
(1992a), Mann et al. (1992), Pinker and Bloom (1990), Silverman and Eals
(1992).
We may question how much of this distinction is editorially imposed and how much
comes from the practitioners themselves. There is sometimes reason to think that
practicing evolutionary psychologists do conceive of their project as falling under
one or the other of these categories. For example, Janet Mann describes her work on
parental investment in explicitly predictive terms. As she describes it, she began by
considering what she took to be a good example of a problem that would have been
faced by our evolutionary ancestors, the problem of whether or not to invest extra
resources in high-risk infants. She then went on to ask what sort of cognitive
mechanisms ought to have developed to assist them in resolving this problem.
(Mann et al. (1992), p.268–390.) Pinker and Bloom, by way of contrast, conceive of
their work on language in much more explanatory terms. They begin with a
well-established complex and integrated information-processing mechanism for
language, complete with several dedicated and interconnected sub-processors for,
e.g., phoneme recognition, lexical analysis, parsing, etc. (Caplan 1992). Their goal
is to show how such a mechanism could possibly have evolved by a standard
adaptive process of incremental change. The ultimate goal of their project is,
presumably, to provide a detailed account of the specific ecological and social
conditions that would correlate with the existence of such a complex and integrated
mechanism.
Even so, we should be sensitive to the possibility that for many practitioners the
distinction is at least partly editorially imposed, for many of them are not so explicit
about their methodology. Even when they are explicit, they sometimes indicate that,
although they would like their project to be seen in exclusively explanatory or
predictive terms, the actual methodology they followed in their research does not
match the description given. So, for example, Cosmides and Tooby describe their
own project involving social exchange in strongly predictive terms. As they describe
it, their research began with a recognition of an adaptive problem supposedly faced
by our ancestors, that of constructing a ‘‘social map of the persons, motives,
interactions, emotions, and intentions that made up their social world’’ (Cosmides
and Tooby (1992a), p. 163.) They then proceeded toward the hypothesis that
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