Positive and negative touch differentially modulate metacognitive memory judgements for emotional stimuli

Touch plays a crucial role in providing humans with information from the external environment and can be perceived by humans as positively or negatively valenced. It is well documented that touch can differentially influence social functions, but very little is known about how touch can modulate (meta)cognition. Utilizing a within-subject design, participants were exposed to (a) positive, (b) negative, and (c) no touch, alongside encoding of emotionally valenced (positive and negative) images. After a 20-minute delay, participants completed a Yes/No recognition task to investigate how touch influenced memory-related decision components (e.g. criterion, confidence). Results showed that, compared to the control condition, both positive and negative touch were associated with overall lower confidence ratings, a less liberal response bias and slower response times. Interestingly, for correct recognitions, only negative touch (vs. no touch) led to inappropriately lower confidence and slower response times while both confidence and response time remained unaltered in positive touch. Our findings provide the first evidence that positive and negative touch differentially interact with metacognitive memory-related decisions. Altered metacognitive judgements after being touched could have significant consequences in applied settings, such as situations of eyewitness testimony.