Heart Rate as a Discriminative Stimulus

Two experiments were performed to evaluate characteristics of heart activity as discriminative stimuli. In Study I two multiple baseline across subjects designs were utilized to assess the efficacy of trial and error and fading procedures in increasing the detection of heart rate activity above and below an average level. Both trial and error and fading procedures were effective in increasing discrimination accuracy. A 4.4 bpm interval around the subject's mean heart rate was employed as the discriminative stimulus in Study II. Significant stimulus control exerted by the criterion stimuli was found during both training and testing conditions. Experimental procedures were discussed for determining which sensory events in a complex stimulus dimension such as a physiological change are actually exerting stimulus control.