Costly ritualized actions induce trust in young children

The prevalence of costly rituals across different cultures could be viewed as confusing from an evolutionary perspective. Against this are suggestions they function as group-wide signals of commitment, increasing trust between group members. Given young children demonstrate an inherent sensitivity to ritual performance, using a three-way between-groups experimental design, the current study tested whether 3- to 6-year-olds perceive those who perform costly rituals as more trustworthy than those who do not. Children (N = 101) participated in two trials, each involving watching a video where a ritual-displaying and non-ritual-displaying informant attempt a task. Ritual cost, constant across both trials participants experienced, was manipulated by the deficit in reward stickers (zero, three, or five) the ritual informant had forgone by choosing to attempt the task in a less efficient, ritualized manner. Both informants then provided conflicting information about an item. After watching the video, children were asked to demonstrate selective trust by endorsing the ritual or non-ritual informant’s testimony. Children trusted the ritual informant more as the cost associated with ritual performance increased. These findings align with the costly signaling hypothesis, suggesting a utility of costly rituals is to increase trust, and that sensitivity to this emerges early in development.