Does it always work? Temporal stability of psychological and physiological responses evoked by slow stroking

Slow gentle stroking of the hairy skin, also called affective touch, has both psychological (i.e., pleasantness of the sensation, improvement of mood state) and physiological (e.g., decrease in heart rate) effects. These effects show considerable individual differences; temporal stability of the individual responses is implicitly assumed in the literature but it has never been empirically investigated. 57 young individuals participated in a preregistered study that assessed experiential and physiological effects of slow (3 cm/s) and fast (30 cm/s) stroking delivered on their forearms two times (eight weeks apart). Pleasantness of the skin sensation showed considerable temporal stability (r = 0.73, p < .001), whereas improvement of mood state was less stable over time (r = 0.53, p < .001). Actual (heart rate, skin conductance level, respiratory rate, skin temperature) and perceived (heart rate, respiratory rate, skin temperature) physiological responses to slow stroking were characterized only by moderate stability. Finally, a considerable discordance between actual responses and their perceived counterparts was found. In conclusion, pleasantness of slow stroking can be considered a trait-like characteristic; changes in mood state and physiological responses are less stable, i.e., they might be substantially impacted by situational factors.