Comparisons of two measures of free-operant avoidance under two conditions of response feedback

Lever-pressing responses of 6 rats were studied under a free-operant avoidance procedure, in 6 two-hour sessions. Three of the subjects were given an added visual feedback for each response; they avoided shocks more effectively than the subjects without the feedback. Two different measures of overall performance in free-operant avoidance were applied to the results of the experiment. There was little difference between the measures: both reflected the subjects' performance equally well. Relative merits of the measures and the criteria for selecting one of them were discussed.