Strengths and weaknesses of affective touch studies over the lifetime: A systematic review.

C-Tactile (CT) fibers are activated by slow, caress-like stimulations, and convey a specific tactile processing of hedonic and interpersonal components, defined as affective touch. Given the beneficial effects deriving from affective tactile experiences in social interactions at all ages, a systematic review of experimental studies on affective touch perception across the lifespan was performed with the aims of 1) examining whether and how affective touch has been studied in a systematic manner throughout the lifespan; 2) verifying whether the pleasantness associated to affective stimulations is found during the entire lifespan. Empirical human studies on affective touch were searched in two databases (PubMed, PsychINFO) and 112 articles were retrieved. Results indicated that most of the studies recruited participants with a mean age ranging from 18 to 40 years, whereas other age ranges came out as under-represented or not represented at all. Despite high heterogeneity across studies, affective touch was considered as a pleasant experience across the lifetime, and it was associated to specific psychophysiological patterns in infants and adults.