“Atheists and Agnostics Are More Reflective Than Religious Believers: Four Empirical Studies and a Meta-Analysis”, 2016-03-21 (; similar):
Individual differences in the mere willingness to think analytically have been shown to predict religious disbelief. Recently, however, it has been argued that analytic thinkers are not actually less religious; rather, the putative association may be a result of religiosity typically being measured after analytic thinking (an order effect).
In light of this possibility, we report 4 studies in which a negative correlation between religious belief and performance on analytic thinking measures is found when religious belief is measured in a separate session. We also performed a meta-analysis on all previously published studies on the topic along with our 4 new studies (n = 15,078, k = 31), focusing specifically on the association between performance on the Cognitive Reflection Test (the most widely used individual difference measure of analytic thinking) and religious belief.
This meta-analysis revealed an overall negative correlation (r) of -0.18, 95% CI [-0.21, -0.16]. Although this correlation is modest, self-identified atheists (n = 133) scored 18.7% higher than religiously affiliated individuals (n = 597) on a composite measure of analytic thinking administered across our 4 new studies (d = 0.72).
Our results indicate that the association between analytic thinking and religious disbelief is not caused by a simple order effect. There is good evidence that atheists and agnostics are more reflective than religious believers.