For the essentialist system, input conditions include the following: (1)
some living things are presented as having common external fea-
tures—a prototype; (2) they are all born of other members of the same
category; (3) there is no reproduction outside the category. This obvi-
ously is the case for species of living things. But social categories are
often presented in this way too. In many places in Africa and Asia
craftsmen are members of endogamous castes that are thought to be
inferior, polluting and dangerous. These groups are explicitly con-
strued as based on natural qualities—the people in question are
thought to be essentially different from the rest, by virtue of some
inherited, internal quality. Blacksmiths in West Africa are recogniz- [287]
able, they are all descended from blacksmiths—you cannot becomea
member of that category—and they only marry blacksmiths. Once a
social category is construed in this way, it should probably activate, in
a decoupled manner, the essentialist inference system.
But this, too, raises difficult questions. So far, we have described
the mechanics of essentialism, the way it activates inference systems
we all have by virtue of how our brains are constructed. But this does
not explain why essentialist construals of social groups appear so con-
vincing and why they trigger such enormous emotional effects. It is
easy enough to understand why social groups are often defined as
essentially different, given the way our brains work. But why is it so
easy to trust members of one's own group and to distrust outsiders,
even without any actual experience of how they behave? Do we
believe that outsiders are unreliable cooperators simply because others
have told us so? Certainly, but the problem is to explain why such
descriptions are so easy to believe.
ESSENCE CONCEPTS AND
COALITIONAL INTUITIONSOne of the most solid and famous findings of social psychology is that
it is trivially easy to create strong feelings of group membership and
solidarity between arbitrarily chosen group members. All it takes is to
divide a set of participants and assign them to, say, the Blue group and
the Red group. Once membership is clearly established, get them to
perform some trivial task (any task will do) with members of their
team. In a very short time, people are better disposed toward mem-
bers of their group than toward the others. They also begin to per-
WHYDOCTRINES, EXCLUSION AND VIOLENCE?