Rituals are performed within specific socio-ecological niches, yet the different effects of the same ritual form across different niches (community contexts) remains unclear. Here, using longitudinal measures over a two-week period during Diwali (the Indian festival of light), we investigate the relationship between ritual time allocation and social cohesion in two Indian communities. First, the positive effects of ritual on social bonding, perceived health and affect were highest on the focal day of the festival. Second, we observed anticipatory effects of ritualistic commitment on affect prior to the main day of the festival. Third, social bonding patterns were similar in the two Indian settings, indicating that Diwali fosters social cohesion across diverse social ecologies (cultural niches). However, individually focused emotional benefits appear to dampened in more cosmopolitan environments. Finally, time investments reveal diminishing marginal utilities for ritual activities on social cognition. Ritual time investments were linked to greater affect and family cohesion up to a certain limit. We argue that attention to the diminishing returns of ritual time investments on social cohesion across diverse human ecologies is an important horizon for future cross-cultural investigations. This article is part of the theme issue 'Ritual renaissance: new insights into the most human of behaviours'.
Keywords: Diwali; collective ritual; niche construction; signalling theory; social bonding.