Habituation of cardiac components of the orienting reflex to stimuli repeated at fixed and variable intervals

The purpose of this study was to determine the effects of fixed-interval (FI) stimulus repetition on cardiac components of the orienting reflex (OR). It was predicted that variable stimulus repetition would lead to habituation of the OR. whereas a fixed (temporal conditioning) interval paradigm would inhibit such habituation. Thirty-six Ss were employed. The main hypothesis concerning the effects of FI stimulus repetition was confirmed. In addition, the data supported the use of Lang & Hnatiow’s (1962) peak-to-valley measure of the cardiac response, although the response appeared to be monophasically decelerative. not diphasic. The results suggest that stimuli having “signal functions” will continually elicit the OR. whereas stimuli not having such functions eventually lose their value as OR elicitors.