Vigilance and the reinforcing properties of shock

There have been some observations to indicate that waiting for a shock is stressful, that the coining of an anticipated shock can serve as a tension reliever, and that failure to obtain an anticipated shock is more stressful than being shocked. Based on these observations, the following hypotheses were tested. If it is true that failure to receive shock is more stressful than the shock itself, it should be possible to train an animal to bring on a shock that had failed to come when anticipated. If a period of anticipating shock is stressful, and shock serves as a reliever of the stress, it should be possible to train an animal to perform a response instrumental to bringing on the shock sooner. Results indicated that shock does seem to serve as a reliever, that waiting for shock is stressful, but that failure to receive an anticipated shock under these circumstances is not more stressful than the shock itself. In addition, it was found that subjects learned to produce shock instrumentally if the shock was inevitable and could thus be brought about sooner. Results were inconclusive, though generally negative, on the issue of whether S’s would produce an avoidable shock that had failed to come when anticipated.