I'm pretty much going in the direction of an Experimental Psychology http://en.wikipedia.org/wiki/Experimental_psychology, because we have an okay understanding of the psychology of religious groups, but we have a lot to learn about the psychology of secular groups; what makes them tick, what, if you built it they would come, because it has elements that resonate in that "secular" person.. Both religious and secular groups need to be understood deeply if we are to understand the difference between the two.
And what is a "secular" person? We all are, with rare exception now, immersed in secular society in varying degrees. Even the Bible believing Christian is secularized.. The topic of Secularization http://en.wikipedia.org/wiki/Secularization is important to me and is a topic of Sociology.
Secularization, according to Wikipedia, is "the transformation of a society from close identification with religious values and institutions toward non-religious (or "irreligious") values and secular institutions. Secularization thesis refers to the belief that as societies "progress", particularly through modernization and rationalization, religion loses its authority in all aspects of social life and governance."
So I will be using Experimental Psychology and a Sociological understanding of Secularization to understand this more deeply..