The effects of control and lack of control on active and passive avoidance in rhesus monkeys

Most studies which have examined the effects of lack of control have utilized test tasks in which active responding is required, and generally they have found impaired learning. Those few studies which have required passive responding in the test task generally have found facilitation of learning. The present two experiments examined the effects of lack of control in both active and passive avoidance tasks in a primate species (Macaco mulatta) not previously used in this research area. In Experiment 1, although the group without control (IE) tended to be inferior at active and superior at passive avoidance in comparison to the group with control (E), there were no significant differences. In Experiment 2, utilizing a difficult discrimination task in which subjects were required to learn when and when not to respond actively to avoid aversive stimulation, greater group differences were found. Two monkeys from Group IE failed to escape in active avoidance acquisition and, as a whole. Group IE was somewhat slower to respond than Group E. At passive avoidance, however. Group IE was superior to Group E and, as a consequence, more efficiently solved the discrimination problem. Implications of the present results for interpretation of the effects of lack of control as deficits are discussed.