Here is a book explaining the mechanism of "cognitive dissonance". It's one of the driving forces of cults like UBF. Leaders create a cognitive dissonance for instance by letting people deliver sogams and life testimonies, or by giving them different names, or by simply letting them take part in group activity though they don't really want to. The result is that the person sooner or later feels obliged to believe the things they have spoken or done. I think we haven't yet fully understood the power of this psychological phenomenon. It is also driving the leaders of UBF, not only the simple members.