Pleasure & Emotion: An Investigation of Physiological Responses Emerged by Pleasant Stimuli

Now that consumers expect everything they buy to be both functional and easy to use, designers need to think seriously about the pleasure their designs bring to users. The services and products with which we surround ourselves are potential sources of pleasure. They should be designed with a view to how they can provide pleasure to those who use and experience them. This study discussed the importance of pleasure for our life. It aims at investigating the critical physiological responses that are emerged by pleasant stimuli. Various physiological responses of the brain (encephaloelectrogram; EEG), autonomic nervous system (ANS), immune system and endocrine system were monitored when pleasant stimuli such as odors, emotional pictures and rakugo, a typical Japanese comical story-telling, were presented to subjects. The results revealed that (i) EEG activities of the left frontal brain region were enhanced by a pleasant odor; (ii) emotional pictures related to primitive element such as nudes and erotic couples elevated vasomotor sympathetic nervous activity; and (iii) an increase in salivary immunoglobulin A (s-IgA) and a decrease in salivary cortisol (s-cortisol) were induced by rakugo-derived linguistic pleasant emotion. Positive emotion is complicated state. However, by considering the evolutionary history of human being, it is possible to assess and evaluate positive emotion from certain physiological responses by appropriately summating various physiological parameters.