Pilot study on the biological responses to pleasant video stimuli in different intensities

To provide evidence-based measures in health management and offer comfort services, it is important to assess emotions objectively. Recently, positive psychology has garnered considerable attention, and its effects have been verified as an early recovery effect during rehabilitation. In this study, to investigate the relationship between the biological responses corresponding to pleasant stimuli and elicited subjective strengths of pleasure, an experiment was conducted using sports videos with different pleasure strengths; in addition, biological responses were measured with collecting subjective ratings and analyzed. The two-minute length video stimuli for the experiment were set, such that the elicited pleasant strengths differed in the preliminary survey. In total, 15 healthy adults participated in the study. Photoplethysmography, respiratory waves, electrocardiograms, and continuous blood pressure waves were measured and analyzed. In the results, although the stimuli used here elicited pleasant emotions, a problem in setting the proper strengths still remained. Regarding biological responses, systolic blood pressure, pulse pressure, and combined parameters of blood pressure wave components exhibited significant differences between stimulus levels. Finally, the combined parameters of the blood pressure wave components exhibited responses of graded intensity, and the magnitudes of these parameters were correlated with subjective rating scores.