The functional properties of a time out from an avoidance schedule

Investigations are reported of some of the discriminative (cue) and reinforcing properties of stimuli (TO_av) correlated with the discontinuation of a free-operant avoidance schedule. After several unsuccessful initial attempts to demonstrate the positively reinforcing effect of TO_av, a special technique was developed. The subjects were trained by means of a free-operant avoidance procedure to press a lever and postpone electric shock; by pressing a second lever, they could produce a cue correlated with the TO_av period. The importance of a distinct cue correlated with TO_av was demonstrated in experiments in which this signal was eliminated from the procedure. The reinforcing function of the TO_av period was explored by showing its effectiveness under various schedules of reinforcement.

Other observations were made concerning the course of extinction of both TO_av-producing responses and avoidance behavior.

In further experiments in which TO_av was used as a reinforcer, the TO_av behavior was also brought under separate stimulus control. The development of the various discriminations involved in the resulting performance were described.