Obviously a person’s religious affiliation will be influenced by cultural factors as well as family history. However, based upon studies in twins who were raised apart, there have been findings that religiosity – a person’s depth of religious feeling and adherence to a religion’s rules – does have a genetic component (Wade & Tavris, 2008). These authors contend that the heritability of religiosity is mediated by the heritability of personality traits. In a study of liberal and fundamentalist Protestant Christians, the fundamentalists scored much lower than the liberals on the dimension of “openness to experience” (Streyffeler & McNally, 1998). When religiosity combines with conservatism and authoritarianism (an unquestioning trust in authority), the result is a deeply ingrained acceptance of tradition and dislike of those who question it (Olson, et al., 2001; Saucier, 2000).
Olson, J.M., Vernon, P.A., Harris, J.A., & Jang, K.L. (2001). The heritability of attitudes: A study of twins. Journal of Personality and Social Psychology, 80, 845-850.
Saucier, G. (2000). Isms and the structure of social attitudes. Journal of Personality and Social Psychology, 78, 366-385.
Streyffeler, L.L., & McNally, R. J. (1998). Fundamentalists and liberals: personality characteristics of Protestant Christians. Personality and Individual Differences, 24, 579 – 580.
Wade, C., & Tavris, C. (2008). Invitation to Psychology (4th Edition). Pearson; Upper Saddle River, NJ.
So, it is true, those people are fundamentally different (no pun, intended).