In-group reassurance in a pain setting produces lower levels of physiological arousal: Direct support for a self-categorization analysis of social influence

A large body of research demonstrates a strong social component to people's pain experiences and pain-related behaviours. We investigate this by examining the impact of social-influence processes on laboratory-induced pain responses by manipulating the social-categorical relationship between the person experiencing pain and another who offers reassurance. We show that physiological arousal associated with laboratory-induced pain is significantly lower in normal, healthy participants following reassurance about the pain-inducing activity when that reassurance comes from an ingroup member in contrast to reassurance from an out-group member and a no reassurance control. These data are consistent with predictions derived from self-categorization theory, providing convincing empirical support of its analysis of social influence using a non-reactive measure. These data also represent a clear advance within the pain literature by identifying a possible common process to the social-psychological component of pain responses.