'These findings indicate that although compassion is associated with pro-sociality among both less religious and more religious individuals, this relationship is particularly robust for less religious individuals.'The study comprised three experiments from the standard canon of tests for pro-social behaviour involving pre-exposure of individuals from each group to certain stimuli and measuring their subsequent willingness to share sums of money with strangers. The article does not quote any figures or error bars from the study but assuming the results were significant it does bear some speculating as to why non-religious people come out as the more compassionate.
The online atheist community has shown frequent evidence of its willingness to rally together for various causes. Scholarship funds for Jessica Ahlquist and Damian Fowler raised tens of thousands of dollars when their atheism made them objects of hate within their community. Charitable organisations like Foundation Beyond Belief, and the atheist groups at the micro lending site Kiva are also exceptionally well supported. This of course goes against the religious script that we need God to be good. We are good regardless of gods, but belief in gods it seems may limit our capacity for goodness.