This study examined the effects of spontaneous laughter on the autonomic nervous system (ANS) activity. Fifteen healthy young men were assigned to receive three 10-min experimental treatments: watching an emotionally moving film (control condition: CON), watching a comedy film (spontaneous laughter: SP), and CON with simulated laughter (SI). A significant interaction between time and treatment was noted in the ANS and the subjective emotional score. During the treatment period, the low-frequency power spectrum was significantly higher under SP conditions than under SI and CON conditions. The present findings suggest that the ANS can differentiate spontaneous laughter from simulated laughter.
