Multiple forms of value learning and the function of dopamine

This chapter describes behavioral evidence for distinct value functions. A classical economic notion of choice assumes that people evaluate options according to their expected utilities. Human and animal actions, however, are not nearly so unitary. Psychologists have long attempted to distinguish bona fide decisions from other behaviors, such as reflexes, that might only appear to be choice-like. In one view, for an action to qualify as truly volitional or goal-directed it should depend on two factors, which echo the probability and utility of an outcome from the standard formula for expected utility. The first is knowledge of the contingency between the action and some outcome; the second is the valuation of that outcome as a desirable goal. A critical distinction between reflexive responses and goal-directed actions is that the latter are controlled by knowledge of their relationship to their consequences whereas the former are not. Classic examples of reflexive responses that have a misleading veneer of choice-like goal-directedness about them can be found in simple conditioning situations.