Collective rituals have long been assumed to play a role in increasing social assimilation and forging emotional bonds between group members. Émile Durkheim described a feeling of belonging and emotional alignment produced by ritual participation, which he called “collective effervescence”. Although this notion has informed generations of anthropologists, it has been notoriously difficult to quantify, while little is known about the physiological mechanisms underlying this effect. In a recent field study, we used physiological measurements alongside traditional ethnographic methods to operationalize and quantify this notion. I discuss the implications of these findings and the use of laboratory methods in field research.