Longing for touch and the vicarious perception of CT-optimal touch in clinical outpatients

Longing for touch (LFT) can be defined as a discrepancy between the amount of touch that is desired and received. Previous studies have shown that LFT is prevalent in non-clinical populations, and that it is associated with an altered perception of CT-optimal touch. However, little is known about the prevalence and potential perceptual consequences of LFT in clinical populations. It is important to investigate this given the complicated relation with social touch that is often observed in these populations. We therefore assessed LFT in 69 clinical outpatients and 136 control participants in this study. Two videos were used to evaluate the vicarious perception of CT-optimal (3 cm/s) and CT non-optimal touch (30 cm/s). LFT was found to be more prevalent and severe in clinical outpatients. While patients also reported a lower frequency of touch, their subjective touch wish did not differ significantly from control participants. The increased LFT of the patients therefore seems to be primarily driven by an absence of touch, rather than a stronger need for touch. In both groups, LFT was positively associated with the vicarious pleasantness perception of CT-optimal and CT non-optimal touch. This provides further support for the hypothesis that LFT enhances the hedonic value of social touch. Taken together, these results provide valuable new insights into the experience and perception of social touch in clinical populations.