Rapid and Unpredictable Shifts in Perceived Pleasantness of Continuous Affective Touch.

Affective touch (stroking the skin at velocities between 1 and 10 cm/s) is generally perceived as pleasant. However, this pleasant sensation diminishes with continuous stimulation over several minutes, with substantial individual variability in the habituation process. This study aimed to identify individual characteristics associated with the decline in the hedonic value of prolonged affective touch. Eighty-one female participants (mean age = 26 years) received continuous stroking on their forearms for 10 min at two distinct velocities: 3 cm/s (affective touch) and 30 cm/s (nonaffective touch). Every 100 s, participants rated the perceived pleasantness of the stimulation. Regression analyses were conducted to examine whether participants' age, attitude toward touch by an unfamiliar person, recalled positive touch experiences during childhood, sympathy toward the toucher, reported symptoms of anxiety, depression, or somatization, and order of touch conditions predicted changes in their responses. On average, the perceived pleasantness of touch declined over time. The extent of the decline and individual variability in pleasantness ratings were not significantly associated with the selected predictors. However, higher overall ratings of affective touch pleasantness were linked to greater sympathy toward the toucher, lower levels of depression and somatization, and a lower frequency of recalled positive touch experiences during childhood. Affective touch was perceived as more pleasant when it was preceded by the nonaffective touch condition, compared to when the order was reversed. Order effects, the rapid decline, and substantial individual variability in the perceived pleasantness of prolonged affective touch should be considered in both research and therapeutic applications.