Bliss in and Out of the Body: The (Extra)Corporeal Space Is Impervious to Social Pleasant Touch

Abstract

Slow, gentle stimulation of hairy skin is generally accompanied by hedonic sensations. This phenomenon, also known as (positive) affective touch, is likely to be the basis of affiliative interactions with conspecifics by promoting inter-individual bindings. Previous studies on healthy humans have demonstrated that affective touch can remarkably impact behavior. For instance, by administering the Rubber Hand Illusion (RHI) paradigm, the embodiment of a fake hand enhances after a slow, affective touch compared to a fast, neutral touch. However, results coming from this area are not univocal. In addition, there are no clues in the existing literature on the relationship between affective touch and the space around our body. To overcome these lacks, we carried out two separate experiments where participants underwent a RHI paradigm (Experiment 1) and a Visuo-Tactile Interaction task (Experiment 2), designed to tap into body representation and peripersonal space processing, respectively. In both experiments, an affective touch (CT-optimal, 3 cm/sec) and neutral touch (CT-suboptimal, 18 cm/sec) were delivered by the experimenter on the dorsal side of participants’ hand through a “skin to skin” contact. In Experiment 1, we did not find any modulation of body representation—not at behavioral nor at a physiological level—by affective touch. In Experiment 2, no visuo-tactile spatial modulation emerged depending upon the pleasantness of the touch received. These null findings are interpreted in the light of the current scientific context where the real nature of affective touch is often misguided, and they offer the possibility to pave the way for understanding the real effects of affective touch on body/space representation.

My social comfort zone: Attachment anxiety shapes peripersonal and interpersonal space

“…First, in an exploratory study, we tested whether embodied social support (by using affective versus neutral touch 40 ) and social observers, modulate the perception of the space surrounding our body, while also secondarily exploring the role of attachment anxiety. Although we found no evidence of change in PPS after affective touch as compared to neutral touch (as in 51 ), or that such effects were moderated by attachment anxiety, we found that the differentiation between peripersonal and extrapersonal space depended on attachment anxiety and the particular social context. To further investigate this effect, and to exclude that it depended on our tactile manipulations, we conducted a follow-up, preregistered study assessing PPS representation as a function of individual differences in attachment anxiety.…”

“…The original hypothesis on the role of affective touch in modulating PPS in social context was not confirmed, consistent with previous research that also found no effect of affective versus neutral touch. 51 However, this first exploratory study indicated that the boundaries between peripersonal and extrapersonal space may depend on the combined effects of social context and attachment anxiety, with people scoring higher in attachment anxiety showing a less defined PPS in the presence of a stranger versus alone in comparison to people with lower scores in this dimension.…”

“…In experiment 1, a skin area (9 × 4 cm) was marked on the participant’s left forearm (i.e., stimulation site). While the only other study investigating the role of affective touch on PPS used skin-to-skin touch, 51 here we used a soft make-up brush to deliver the slow, affective and very slow, neutral touch. On the one hand, using a soft brush to deliver the touch, as compared to skin-to-skin contact, allows us greater experimental control over confounding factors such as differences in skin temperature, sweating rates, etc.…”

Multisensory contributions to affective touch

“…Nowadays, such findings make sense in terms of affective touch (stroking) leading to greater incorporation of the seen body into the body image. In such cases, note, the type of touch (affective or not) modulates the extent of vision's dominance over proprioception, and thus bodily incorporation (Jenkinson, Papadaki, Besharati, Moro, Gobbetto, Crucianelli, et al, 2020;Panagiotopoulou, Filippetti, Tsakiris, & Fotopoulou, 2017; though see also Spaccasassi, Frigione, & Maravita, 2021).…”

Body–Space Interactions: Same Spatial Encoding but Different Influence of Valence for Reaching and Defensive Purposes

“…Integration of visual and tactile stimuli is enhanced when the visual stimulus is closer to the body rather than far away from it, as revealed by electrophysiological studies in monkey (Graziano, Reiss, & Gross, 1999;Duhamel, Bremmer, Hamed, & Graf, 1997;Fogassi et al, 1996) as well as humans (Noel, Serino, & Wallace, 2019;Bernasconi et al, 2018). In humans, there is also considerable behavioral evidence for multisensory enhancement within PPS (Spaccasassi, Frigione, & Maravita, 2021;Spaccasassi, Romano, & Maravita, 2019;Serino et al, 2015;Brozzoli, Makin, Cardinali, Holmes, & Farnè, 2011;Makin, Holmes, Brozzoli, Rossetti, & Farne, 2009;Làdavas, Pellegrino, Farnè, & Zeloni, 1998).…”