AUTHOR=Bulbulia Joseph, Xygalatas Dimitris, Schjoedt Uffe, Fondevila Sabela, Sibley Chris, Konvalinka Ivana TITLE=Images from a jointly-arousing collective ritual reveal affective polarization JOURNAL=Frontiers in Psychology VOLUME=4 YEAR=2013 URL=https://www.frontiersin.org/articles/10.3389/fpsyg.2013.00960 DOI=10.3389/fpsyg.2013.00960 ISSN=1664-1078 ABSTRACT=Collective rituals are biologically ancient and culturally pervasive, yet few studies have quantified their effects on participants. We assessed two plausible models from qualitative anthropology: ritual empathy predicts affective convergence among all ritual participants irrespective of ritual role; rite-of-passage predicts emotional differences, specifically that ritual initiates will express relatively negative valence when compared with non-initiates. To evaluate model predictions, images of participants in a Spanish fire-walking ritual were extracted from video footage and assessed by nine Spanish raters for arousal and valence. Consistent with rite-of-passage predictions, we found that arousal jointly increased for all participants but that valence differed by ritual role: fire-walkers exhibited increasingly positive arousal and increasingly negative valence when compared with passengers. This result offers the first quantified evidence for rite of passage dynamics within a highly arousing collective ritual. Methodologically, we show that surprisingly simple and non-invasive data structures (rated video images) may be combined with methods from evolutionary ecology (Bayesian Generalized Linear Mixed Effects models) to clarify poorly understood dimensions of the human condition.