the brain that is imagining performing the action witnessed, although
the plan is not made consciously and the motor sequence is inhibited.
Infants seem to have the same system minus the final inhibition, which
leads them to imitate other people's gestures. This may be the explana-
tion for that famous and rather surprising experimental result, that
people who merely watchothers practice a particular sport actually get
better at that sport (not quite as much as those who actually practiced,
unfortunately). So seeing other people's actions or motions as some-
thing we might be doing is the job of yet another specialized system.
There is now evidence that representing other people's pain is the
output of yet another specialized neural structure. Some sets of neu- [105]
rons respond selectively to excessive heat, cold and pressure. Other,
neighboring areas respond selectively to similar events affecting other
people. The fact that we have specific emotional reactions to seeing
pain inflicted on other people may result from the simple simulation
produced by this system. That is, the experience of other people's pain,
as handled by the brain's dedicated structures, to some extent overlaps
with that of one's own pain. Again, there is a system that produces some
description of how events affect other persons (in terms of a close sim-
ulation of what it would be like for us to experience the events) but that
is concerned only with a narrow aspect of these events.^8
To sum up, then, our internal description of other people's mental
life is not the product of a single, general theory of persons but the out-
come of many different perceptions, simulations and inferences about
different aspects of what they experience. What seemed a unified
domain of "intuitive psychology" is in fact a collection of subdomains
with specialized systems. The same applies to other domains of the
mental encyclopedia. For instance, we seem rather good at detecting
that some objects in the world (e.g., animals and people) move in pur-
suance of various goals, while others (rocks, rivers, trees, etc.) move only
because of some external force. Now some simple detection mecha-
nisms seem to distinguish between these objects on the basis of motion
itself. That is, the motion of animate beings is typically less uniform in
velocity, more erratic in direction, than that of inanimate things. But
motion is not the only criterion. Animate beings often provide cues that
they are attending to other objects in their surroundings. Animals for
instance turn their heads to follow the objects they are interested in. In
this domain, again, we find that what seemed to be a simple process—
find which objects are goal-driven and which are not—requires the col-
laboration of several more specialized neural systems.
THEKIND OF MINDITTAKES