Who Needs Emotions? The Brain Meets the Robot

an evolutionary theory of emotion 135
the basal ganglia may allow rapid actions. Another is when there may be
too many factors to be taken into account easily by the explicit, rational,
planning system when the implicit system may be used to guide action. In
contrast, when the implicit system continually makes errors, it would be
beneficial for the organism to switch from automatic, direct action based
on obtaining what the orbitofrontal cortex system decodes as being the most
positively reinforcing choice currently available to the explicit, conscious
control system, which can evaluate with its long-term planning algorithms
what action should be performed next. Indeed, it would be adaptive for the
explicit system to regularly assess performance by the more automatic system
and to switch itself to control behavior quite frequently as otherwise
the adaptive value of having the explicit system would be less than optimal.
Another factor which may influence the balance between control by the
implicit and explicit systems is the presence of pharmacological agents such
as alcohol, which may alter the balance toward control by the implicit system,
may allow the implicit system to influence more the explanations made
by the explicit system, and may within the explicit system alter the relative
value it places on caution and restraint versus commitment to a risky action
or plan.
There may also be a flow of influence from the explicit, verbal system
to the implicit system such that the explicit system may decide on a plan of
action or strategy and exert an influence that will alter the reinforcement
evaluations made by and the signals produced by the implicit system. An
example of this might be that if a pregnant woman feels that she would like
to escape a cruel mate but is aware that she may not survive in the jungle,
then it would be adaptive if the explicit system could suppress some aspects
of her implicit behavior toward her mate so that she does not give signals
that she is displeased with her situation. (In the literature on self-deception,
it has been suggested that unconscious desires may not be made explicit in
consciousness [or actually repressed] so as not to compromise the explicit
system in what it produces; see Alexander, 1975, 1979; Trivers, 1976, 1985;
and the review by Nesse & Lloyd, 1992). Another example is that the explicit
system might, because of its long-term plans, influence the implicit
system to increase its response to a positive reinforcer. One way in which
the explicit system might influence the implicit system is by setting up the
conditions in which, when a given stimulus (e.g., a person) is present, positive
reinforcers are given to facilitate stimulus–reinforcement association
learning by the implicit system of the person receiving the positive reinforcers.
Conversely, the implicit system may influence the explicit system, for
example, by highlighting certain stimuli in the environment that are currently
associated with reward, to guide the attention of the explicit system
to such stimuli.