title: Images from a jointly-arousing collective ritual reveal affective polarization.
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.
authors.affiliation: Faculty of Humanities and Social Sciences, Victoria University of Wellington Wellington, New Zealand ; LEVYNA Laboratory for the Experimental Research of Religion, Masaryk University Brno, Czech Republic.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Bulbulia
authors.affiliation: LEVYNA Laboratory for the Experimental Research of Religion, Masaryk University Brno, Czech Republic ; Interacting Minds Center, Aarhus University Aarhus, Denmark.
authors.forename: Dimitris
authors.initials: D
authors.lastname: Xygalatas
authors.affiliation: Interacting Minds Center, Aarhus University Aarhus, Denmark.
authors.forename: Uffe
authors.initials: U
authors.lastname: Schjoedt
authors.affiliation: Center for Human Evolution and Behavior, Universidad Complutense de Madrid Madrid, Spain.
authors.forename: Sabela
authors.initials: S
authors.lastname: Fondevila
authors.affiliation: Department of Psychology, University of Auckland Auckland, New Zealand.
authors.forename: Chris G
authors.initials: CG
authors.lastname: Sibley
authors.affiliation: Section for Cognitive Systems, Department of Applied Mathematics and Computer Science, Technical University of Denmark Lyngby, Denmark.
authors.forename: Ivana
authors.initials: I
authors.lastname: Konvalinka
keywords: Markov chain Monte Carlo; evolution; fire; multi-level; religion; ritual