ABSTRACT
Semantic confusions have hindered scientific progress in the analysis of the effects of aversive stimuli. R. J. Stein, Sidman and J. V. Brady have shown that the amount of conditioned suppression resulting from a specified shock and pre-shock stimulus also depends on the frequency with which this combination of stimuli is presented. The original investigation was reported by W. K. Estes and B. F. Skinner in a paper which they entitled 'Some quantitative properties of anxiety'. They established consistent patterns of lever pressing in rats by means of a schedule of intermittent food reinforcement. Much interest was shown in the phenomenon as a model which made it possible to evaluate experimentally some of the treatments for human anxiety conditions which are used in clinical practice. Enthusiasm has given way to extreme caution or even to pessimism concerning the general relevance of conditioned suppression to clinical anxiety states.
