Visuo-Motor Affective Interplay: Bonding Scenes Promote Implicit Motor Pre-dispositions Associated With Social Grooming–A Pilot Study

Abstract

Proximity and interpersonal contact are prominent components of social connection. Giving affective touch to others is fundamental for human bonding. This brief report presents preliminary results from a pilot study. It explores if exposure to bonding scenes impacts the activity of specific muscles related to physical interaction. Fingers flexion is a very important component when performing most actions of affectionate contact. We explored the visuo-motor affective interplay by priming participants with bonding scenes and assessing the electromyographic activity of the fingers flexor muscle, in the absence of any overt movements. Photographs of dyads in social interaction and of the same dyads not interacting were employed. We examined the effects upon the electromyographical activity: (i) during the passive exposure to pictures, and (ii) during picture offset and when expecting the signal to perform a fingers flexion task. Interacting dyads compared to matched non-interacting dyads increased electromyographic activity of the fingers flexor muscle in both contexts. Specific capture of visual bonding cues at the level of visual cortex had been described in the literature. Here we showed that the neural processing of visual bonding cues reaches the fingers flexor muscle. Besides, previous visualization of bonding cues enhanced background electromyographic activity during motor preparation to perform the fingers flexion task, which might reflect a sustained leakage of central motor activity downstream leading to increase in firing of the respective motor neurons. These data suggest, at the effector level, an implicit visuo-motor connection in which social interaction cues evoke intrinsic dispositions toward affectionate social behavior.

Neural underpinnings of the interplay between actual touch and action imagination in social contexts

“…The We-Touch condition showed a significantly larger amplitude compared to all the other conditions (Self-Touch, Surface Touch, and No-Touch), while among those, no significant difference was detected. Considering that ADM was not directly involved in the action ( Ali et al, 2023 ), this finding confirms that affective touch may have a more pervasive influence compared to other types of touch, aligning with the idea that the brain is hardwired around social dimensions ( Dunbar, 2010 ), and that, social cues and contexts are processed as exceptionally influential information ( Souza et al, 2012 ; Grichtchouk et al, 2022 ). Affective touch is mediated by a specialized sub-modality of touch, the c-touch system ( McGlone et al, 2014 ), and fMRI evidence suggests that social touch is associated with widespread neural activity ( Boehme et al, 2019 ).…”

“…Considering the touch condition, we hypothesized that the motor system will show higher cortico-spinal activation when biological sources are touched, i.e., when individuals are either touching themselves and when touching someone else, as compared to when they are touching non-living sources, or not touching at all. However, when social interaction is included, we might expect to find higher cortico-spinal activation when touching someone else compared to the self-touch condition since it has been shown that the processing of social information undergoes distinctive and privileged processing mechanisms ( de Oliveira et al, 2012 ; Souza et al, 2012 ; Campagnoli et al, 2015 ; Boehme and Olausson, 2022 ; Grichtchouk et al, 2022 ). Alternatively, participants may perceive self-generated tactile stimulation as relatively weaker, when compared to external tactile stimulation ( Kilteni et al, 2018 ).…”

Characterizing affiliative touch in humans and its role in advancing haptic design

“…Moreover, interactions between sensory modalities may also influence the predisposition to produce affiliative touch. A pair of studies has reported suggestive results indicating that viewing images of bonding versus nonbonding human pairs increased muscle activity in finger flexor muscles and reduced EEG signals of motor readiness prior to the instructed finger movement 77,78 . Such findings highlight the complex interplay between the senses.…”