Abstract
The present study was undertaken to condition HR acceleration instrumentally. 20 Ss were divided into the two groups. After a 15-min rest period, the experimental group received a dim light following each instantaneous HR acceleration during a 20-min reinforcement period, while the control group was matched with the experimental group in the number of lights per min of this period, but the lights were not presented to be contingent upon the occurrences of HR acceleration. Finally a 10-min extinction period was given. The experimental group showed significantly more accelerative HR than the control group during the reinforcement period. These differences were also significantly maintained during the extinction period, but the expected extinction trend was not observed. No significant relationship was obtained between the change of HR and that of respiration rate.