Exploring the impact of gentle stroking touch on psychophysiological regulation of inhibitory control.

Touch has been shown to regulate emotions, stress responses, and physical pain. However, its impact on cognitive functions, such as inhibitory control, remains relatively understudied. In this experiment, we explored the effects of low-force, slow-moving touch-designed to optimally activate unmyelinated cutaneous low-threshold mechanoreceptor C-tactile (CT) afferents in human hairy skin-on inhibitory control and its psychophysiological correlates using the Stroop Task, a classic paradigm commonly employed to assess inhibitory control capacity. The Stroop Task was repeated twice before and once after receiving either gentle touch or no-touch. Participants were assigned to two groups: the touch group (n = 36), which received low-force, slow-moving touch on their forearms at a stroking velocity of ~3 cm/s, and the no-touch group (n = 36), which did not receive any touch stimulation. Changes in autonomic nervous system activity were also assessed by measuring heart rate variability (HRV) and skin conductance levels before and during cognitive performance. Compared to the no-touch group, participants who received gentle, low-force, slow-moving touch demonstrated faster responses and higher HRV during the Stroop Task. Additionally, within the touch group, individuals with higher HRV exhibited even quicker performance on the cognitive task. While we cannot draw definitive conclusions regarding the CT velocity-specific effect, these results provide preliminary evidence that low-force, slow-moving touch may influence cognitive processes involved in the inhibitory control of goal-irrelevant stimuli.