So the literature is clearly a hodgepodge. And even if religion can be linked to an increased susceptibility to violence, the authors point out that this is not unique to religion. “While threat perceptions toward individuals’ religious identities may institute aggressive or violent responses, these effects are a product of a general social psychological process of group behavior, rather than anything inherent to religion,” they write. That is, when ardent adherents of secular ideologies sense threat, they, too, often lash out at outsiders – what’s going on is a fairly universal aspect of social psychology.

There could have been many situations in which researchers, by only asking questions about religion, missed this bigger picture. For example, while attendance at religious services has been associated with increased hostility toward, and intentions to harm, outgroups, it could be that religious attendance is simply a proxy for people having strong in-group identification. It’s plausible that greater attendance at national, sporting or other secular ceremonies, might similarly correlate with hostility towards relevant outgroups – but if the only questions you ask are about religion, the only answers you get will be about religion.