Abstract
Complex discrimination learning by amgdalectomized and control groups of monkeys was analyzed in a modified learning-set problem designed to assess relative discriminative control exercised by rewarded and nonrewarded events. Amygdalectomy seriously impaired performance under all conditions. Similar marked disturbances were noted in discrimination reversals, amygdalectomized monkeys showing negligible interproblem transfer of training. A 3rd experiment confirmed the impairment in learning set and demonstrated further disruption in performance following replacement with a novel object of either (+) or (-) test objects of established discriminations. Amygdalectomy would seem to interfere with discrimination behavior in which changes in stimulus or reinforcing conditions maximize transfer of training.