Elicitation and habituation of the electrodermal activity responses: Implications for neurophysiological applications

Electrodermal activity (EDA) serves as a reliable indicator of sympathetic activation for the measurement of emotional arousal. Despite extensive use of EDA in psychophysiological and neurophysiological research, little is known about how repeated stimulus presentation influences EDA responses, particularly when more than one parameter is measured simultaneously. This study examined the influence of repeated stimulus presentation on three EDA parameters (SCRs, SPRs, and SSRs). A total of sixty healthy subjects participated in the study. They were exposed to four external stimuli: sound, image, taste, and smell. Each of the four stimuli was repeated five times to investigate the effect of their repetition on SCRs, SPRs, and SSRs. Significant (p < 0.001) impacts of repeated stimulus presentation and introducing a novel stimulus on three EDA parameters were observed. The study results indicated that SCRs, SPRs, and SSRs were reduced following stimulus repetitions and habituation, exhibiting exponential decay, and they recovered following a change in stimulus category. This suggests that using different stimuli may better preserve physiological reactivity by limiting within-trial habituation. This information should be considered in neurotechnological applications, such as amygdala function, where repeated presentation of the same stimulus may inadvertently decrease amygdala activation, potentially mimicking volitional downregulation.