ABSTRACTThe purpose of this study is to compare the effects of response‐contingent and random aversive auditory stimulation on gastrointestinal motility.Ss were presented with four consecutive 10‐min treatment periods in the following order: response‐contingent (R‐C), random, R‐C, random. During R‐C,Scould avoid the 5‐sec 90 db tone, which was programmed to come on every 30 sec, by pressing a key once during the 5 sec preceding the tone. During the random period,Shad no control over the presentation of the tone. The results indicated that during R‐C, amplitude of gastrointestinal motility was significantly greater and latency briefer than under random conditions. These results are accounted for in terms of the dual role of the tone in the R‐C condition, i.e. it is aversive and it signifies to S that his time estimat