Abstract
Seven groups of subjects learned an avoidance response (CS-UCS interval = 4.5 sec.) and were then given different treatments of flooding. The 0-sec., 3-sec., 10-sec., and 20-sec. groups were administered the CS for 0, 3, 10, and 20 sec., respectively, on each of the 15 trials. The 10-sec.-variable group was exposed to different durations of CS on 15 trials such that the average exposure per trial was 10 sec. The 3-sec.-exposure-control group was exposed to the CS for 3 sec. on each of the 50 trials. All these groups could make the button-press avoidance response during treatment but the response had no effect on the CS. The CS was offset after the predetermined time. A CS-only group was given 15 trials during which it could terminate the CS by making the button-press avoidance response. Testing during extinction showed that the CS-only, 0-sec., and 3-sec. groups were more difficult to extinguish than the 10-sec. and 20-sec. groups. There was no difference between the 3-sec. and 3-sec.-exposure-control groups. The 10-sec. group showed quicker extinction compared to the 10-sec.-variable and 3-sec.-exposure-control groups. It is argued that flooding is effective when the duration of CS exposure per trial is greater than the CS-UCS interval.