Despite the increase of secularism, implicit religious and spiritual (jointly termed “supernatural”) reasoning persists even in individuals who identify as nonbelievers; however, previous studies...Show moreDespite the increase of secularism, implicit religious and spiritual (jointly termed “supernatural”) reasoning persists even in individuals who identify as nonbelievers; however, previous studies have used behavioral implicit measures to examine differences between implicit and explicit belief. The aim of this research was to investigate these differences in atheist and spiritual-but-not-religious (SBNR) individuals using event-related potentials, and explore the N400-effect as an implicit marker of (un)belief. We conducted two studies: Study 1A (N = 101) examined supernatural attitudes and study 1B (N = 109) examined supernatural beliefs. Participants were presented with positive/negative (1A) and belief/disbelief (1B) religious, spiritual, and control statements, and were asked to provide their explicit evaluation (i.e., agree/disagree) of the statements while ERPs were being recorded. The results showed inconclusive evidence of the utility of the N400 as an implicit measure of belief. Specifically, we did not find significant differences between atheists and SBNR individuals in the N400- amplitude between positive and negative (1A), or belief and disbelief (1B) religious, spiritual, and control statements. In light of the lack of statistically significant results, exploratory analyses were performed, and implications and limitations of our study, as well as suggestions for future research, were discussed.Show less