This thesis presents the results of a multi-method exploration of the effects of collective dysphoric rituals on self-identification, group affiliation, and prosocial behaviour. Findings are presented from a worldwide sample of martial artists, student participants in artificial ritual experiments, and observers and performers of Shinto firewalking festivals in Japan. The thesis tests recent predictions of the Modes of Religiosity theory in regards to the psychological processes that underpin shared dysphoric rituals and various costly signalling theories concerning the group orientated consequences of participating in extreme ritual events. The results from the studies raise questions with the broader generalisability of recent findings linking collective dysphoric rituals and inclusive self- identification and urge for a more nuanced appraisal of associations with prosocial behaviour. Furthermore, the role of subjective positive assessment of dysphoric experiences is shown to be a topic that has been unduly overlooked and preliminary evidence is provided for a potential relationship with identity fusion. Methodologically the thesis presents a series of novel artificial ritual studies that offer initial evidence in support of shared dysphoria's ability to enhance cooperation and promote positive ingroup association.