Madeleine Bregulla

Episodic memories can be shaped by various contextual factors. While social and sensory cues such as odors and music have been shown to influence encoding and retrieval, the role of tactile information remains unclear. In this preregistered study, we investigated the effects of affective touch on face memory. 57 healthy adults (40 women) completed the Cambridge Face Memory Tests and the Social Touch Questionnaire to assess general face recognition ability and attitudes toward social touch. During encoding, participants viewed neutral faces while receiving either static, dynamic, or no touch from a hidden experimenter and rated each face’s attractiveness and trustworthiness. Recognition was tested two days later. Outcome measures included recognition accuracy, metacognitive sensitivity (i.e., the ability of confidence ratings to distinguish between correct and incorrect responses), and judgments of attractiveness and trustworthiness. No significant differences emerged between touch conditions, and neither face recognition ability nor attitudes toward touch moderated these effects. Bayesian analyses provided moderate to strong evidence for the absence of touch effects on recognition accuracy and confidence ratings, whereas evidence regarding metacognitive sensitivity and trustworthiness evaluations was inconclusive. Overall, the findings suggest that brief social touch in a controlled laboratory context has limited measurable effects on face memory, and that richer social context may be required for touch to influence memory processes.

Episodic memories can be shaped by various contextual factors. While social and sensory cues such as odors and music have been shown to influence encoding and retrieval, the role of tactile information remains unclear. In this preregistered study, we investigated the effects of affective touch on face memory. 57 healthy adults (40 women) completed the Cambridge Face Memory Tests and the Social Touch Questionnaire to assess general face recognition ability and attitudes toward social touch. During encoding, participants viewed neutral faces while receiving either static, dynamic, or no touch from a hidden experimenter and rated each face’s attractiveness and trustworthiness. Recognition was tested two days later. Outcome measures included recognition accuracy, metacognitive sensitivity (i.e., the ability of confidence ratings to distinguish between correct and incorrect responses), and judgments of attractiveness and trustworthiness. No significant differences emerged between touch conditions, and neither face recognition ability nor attitudes toward touch moderated these effects. Bayesian analyses provided moderate to strong evidence that brief social touch during encoding does not influence face memory or social evaluations. These findings suggest that brief touch in a laboratory context exerts minimal effects and that meaningful social context may be required for touch to impact memory processes.

Trauma can shape the way an individual experiences the world and interacts with other people. Touch is a key component of social interactions, but surprisingly little is known how trauma exposure influences the processing of social touch. In this review, we examine possible neurobiological pathways through which trauma can influence touch processing and lead to touch aversion and avoidance in trauma-exposed individuals. Emerging evidence indicates that trauma may affect sensory touch thresholds by modulating activity in the primary sensory cortex and posterior insula. Disturbances in multisensory integration and oxytocin reactivity combined with diminished reward-related and anxiolytic responses may induce a bias towards negative appraisal of touch contexts. Furthermore, hippocampus deactivation during social touch may reflect a dissociative state. These changes depend not only on the type and severity of the trauma but also on the features of the touch. We hypothesise that disrupted touch processing may impair social interactions and confer elevated risk for future stress-related disorders.