NATURE OF NONLIMBIC LEARNING

Trained 4 naive rhesus monkeys with combined hippocampal-amygdaloid lesions and 7 unoperated controls postoperatively on a visual discrimination problem, tested for retention after 3 wk., and trained on a reversal task. Ss were profoundly deficient on all but the retention test. The difference between groups in the original learning task was due to the fact that Ss were slow to begin learning. 60-90% learning curves were identical. On the reversal task Ss generated a long plateau around the 50% level of performance. Comparison with similar results on human retardates suggests that ordinarily these limbic structures function to maintain a hypothesis in the face of distraction or disconfirmation. (16 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.