Long Term Retention of Instrumentally Learned Heart-Rate Changes in the Curarized Rat
This chapter aims to determine if the instrumental learning of heart-rate changes rewarded by escape from or avoidance of electric shock displays another important characteristic of the instrumental learning of skeletal responses, namely, long-term retention. In an experiment by L. V. DiCara and J. M. Weiss, it was shown that heart-rate changes learned under curare have a significant effect upon subsequent noncurarized skeletal avoidance learning. Subjects which learned fast heart rate under curare showed poor avoidance learning, while subjects which learned slow heart rate showed significantly better avoidance learning. Heart rate was computed from individual blank trials at the beginning of and at quarterly intervals throughout avoidance training and retention testing. There was a highly significant association obtained between the direction of change in heart rate obtained during the 30-minute period preceding the test for retention and original heart-rate learning, namely, all subjects showed changes in the rewarded direction.