How Good Is the Samaritan, and Why?

What is the extent and nature of religious prosociality? If religious prosociality exists, is it parochial and extended selectively to coreligionists or is it generalized regardless of the recipient? Further, is it driven by preferences to help others or by expectations of reciprocity? We examined how much of a US$0.30 bonus Mechanical Turk workers would share with the other player whose religion was prominently displayed during two online resource allocation games. In one game (but not the other), the recipient could choose to reciprocate. Results from both games showed that the more central religion was in participants' lives, the more of the bonus they shared, regardless of whether they were giving to atheists or Christians. Furthermore, this effect was most clearly related to self-reported frequency of "thinking about religious ideas" rather than belief in God or religious practice/experience. Our findings provide evidence of generalized religious prosociality and illuminate its basis.