Dissociable sources of erogeneity in social touch: Imagining and perceiving C-Tactile optimal touch in erogenous zones.

Previous research points to two major hypotheses regarding the mechanisms by which touch can be experienced as erotogenic. The first concerns the body part to which touch is applied (erogenous zones) and the second the modality of touch (sensual touch optimal in activating C Tactile afferents). In this study, we explored for the first time the relation between those two mechanisms in actual and imagined social touch. In a first experiment, we randomly assigned "Giver" and "Receiver" roles within 19 romantic couples (20 females, 18 males, age 32.34 ± 8.71SD years) and asked the "Giver" to apply CT-optimal (3 cm/s) vs. CT-suboptimal (18 cm/s) touch on an erogenous (neck) vs. non-erogenous zone (forehead) of their partner. We then obtained ratings of pleasantness and sexual arousal from both "Receivers" and "Givers". In a second experiment, 32 healthy females (age 25.16 ± 5.91SD years) were asked to imagine CT-optimal vs. CT-suboptimal stimulation (stroking vs. patting) and velocity (3 cm/s vs. 18 cm/s) on different erogenous vs. non-erogenous zones and rate pleasantness. While both erogenous body part and CT-optimal, sensual touch were found to increase pleasant and erotic sensations, the results showed a lack of an interaction. Furthermore, pleasantness was induced by mere imagination of touch without any tactile stimulation, and touch that was sexually arousing for the receiver was rated as more sexually arousing for the giver as well, pointing to top-down, learned expectations of sensory pleasure and erogeneity. Taken together, these studies provide the first direct evidence that while both the body location to which touch is applied and the mode of touch contribute to pleasant and erotic sensations, these two factors appear to mediate subjective pleasantness and erogeneity by, at least partly, independent mechanisms.