Many studies have suggested a relation between religion and prosocial behavior: religious people tend to be more prosocial (e.g. giving time and money) both in terms of self-report measures and behavioral measures (economic decision games). However, the specific factors underlying the relation between religion and prosociality are not well understood.
In two studies, involving both a field-study and a lab-based experiment using a priming procedure, it was investigated to what extent prosocial behavior is related to 'belief in supernatural punishment' and / or to 'being part of a community of fellow believers'. We found a dissociation between self-report and behavioral measures of prosocial behaviors: religious participants tend to see themselves as more prosocial, but this does not become apparent in actual behavior. In addition, no evidence was found for an effect of belief in supernatural punishment or belonging to a community on prosocial behavior. This project was conducted by Lisanne van Bunderen in collaboration with research agency Motivaction. The outcomes of the project are described in the Research Master thesis.
In another study the relation between costly signaling and prosocial behavior was investigated in a sample of religious participants. The outcomes of this project which was conducted by Olmo van den Akker are described here and the data can be accessed via this link.