Reward anticipation, cognition, and electrodermal activity in the conditioned monkey.

In the present report, we examine electrodermal activity (skin conductance responses, SCRs) in monkeys trained to perform target-selection (TS) tests. In each test, the animal was presented in successive trials with the same two unequally rewarded targets on a touch screen. The probabilistic contingencies of the rewards associated with each target rendered the selection of the best difficult. Our findings revealed SCRs time-locked to the arm movements toward the rewarded targets, occurring after the target touches. Parameters of the SCRs were stable when the uncertainty of the choices and of the outcomes varied. The results support the hypothesis that the physiological processes indexed by the SCRs are the correlate of anticipatory appetitive behavior. In contrast, there is no evidence that the SCRs reflect cognitive processes associated with the detection of the best target.