Orienting and defense responses to punishment: effects on learning.

Two groups of students attempted to learn sequences of letter-number pairs. For both groups, a tone signalled each error. However, for aversive punishment subjects, a mildly painful electric shock followed the tone 20% of the time, whereas the informational punishment subjects received only the tone. Skin conductance responses (SCRs) and cardiac interbeat intervals indicated the presence of an orienting response to the tone in informational punishment subjects and a defense response to the tone in aversive punishment subjects. Accompanying these were significant differences in behavior: aversive punishment subjects completed fewer sequences and had higher error rates. The two groups did not differ in measures of tonic arousal. Session trends suggested that the cardiac orienting response developed in both groups as subjects learned to use the information in the punishment contingency. Defense responses to aversive punishers may complete with orienting responses necessary to the efficient learning of complex tasks.