Who Needs Emotions? The Brain Meets the Robot

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However, it may be expected that there is often a conflict between
these systems in that the first, implicit, system is able to guide behavior
particularly to obtain the greatest immediate reinforcement, whereas the
explicit system can potentially enable immediate rewards to be deferred
and longer-term, multistep plans to be formed. This type of conflict will
occur in animals with a syntactic planning ability (as described above), that
is, in humans and any other animals that have the ability to process a series
of “if . . . then” stages of planning. This is a property of the human
language system, and the extent to which it is a property of nonhuman
primates is not yet fully clear. In any case, such conflict may be an important
aspect of the operation of at least the human mind because it is so
essential for humans to correctly decide, at every moment, whether to
invest in a relationship or a group that may offer long-term benefits or
whether to directly pursue immediate benefits (Nesse & Lloyd, 1992). As
Nesse and Lloyd (1992) describe, psychoanalysts have come to a somewhat
similar position, for they hold that intrapsychic conflicts usually seem
to have two sides, with impulses on one side and inhibitions on the other.
Analysts describe the source of the impulses as the id and the modules that
inhibit the expression of impulses, because of external and internal constraints,
as the ego and superego, respectively (Leak & Christopher, 1982;
Trivers, 1985; see Nesse & Lloyd, 1992, p. 613). The superego can be
thought of as the conscience, while the ego is the locus of executive functions
that balance satisfaction of impulses with anticipated internal and
external costs. A difference of the present position is that it is based on
identification of dual routes to action implemented by different systems
in the brain, each with its own selective advantage.
BRAIN SYSTEMS UNDERLYING EMOTION
Overview
Animals are built with neural systems that enable them to evaluate which
environmental stimuli, whether learned or not, are rewarding and punishing,
that is, will produce emotions and will be worked for or avoided. Sensory
stimuli are normally processed through several stages of cortical processing to
produce a sensory representation of the object before emotional valence is
decoded, and subcortical inputs to, e.g., the amygdala (LeDoux, 2000) will
be of little use when most emotions are to stimuli that require processing to
the object level (Rolls, 1999a). For example, in the taste system, taste is
analyzed in primates to provide a representation of what the taste is in the
primary taste cortex, and this representation is independent of the reward