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.

既往研究针对触觉被感知为催情性的机制提出了两大核心假说：其一涉及触觉施加的身体部位（动情区（erogenous zones）），其二则关乎触觉的作用模式——即激活C类触觉传入纤维（C Tactile afferents）的最优感官触觉。本研究首次探讨了真实社交触摸与想象社交触摸中这两种机制间的关联。在第一项实验中，我们在19对情侣（20名女性、18名男性，年龄为32.34±8.71SD岁）中随机分配给予者（Giver）与接收者（Receiver）角色，要求给予者对伴侣的动情区（颈部）与非动情区（前额）分别施加CT-optimal（3 cm/s）与CT-suboptimal（18 cm/s）的触摸，随后收集了给予者与接收者双方对愉悦感及性唤起程度的评分。在第二项实验中，我们要求32名健康女性（年龄为25.16±5.91SD岁）想象分别对不同动情区与非动情区施加CT-optimal与CT-suboptimal的刺激——涵盖轻抚（stroking）与拍打（patting）两种动作模式，以及3 cm/s与18 cm/s两种刺激速度——并对愉悦感进行评分。研究结果显示，动情的身体部位与CT-optimal的感官触觉均能提升愉悦感与催感性，但二者并未出现交互效应。此外，仅通过想象触摸而非实际触觉刺激即可诱发愉悦感；且能令接收者产生性唤起的触摸，同样会被给予者评为更具性唤起性，这指向了感官愉悦与催感性的自上而下、后天习得的预期机制。综上，本研究首次提供了直接证据：尽管触摸施加的身体部位与触摸模式均能影响愉悦感与催感性，但这两个因素似乎至少部分通过独立的机制介导了个体主观的愉悦感与催感性。