Individuals' beliefs do not change in a vacuum, independent of each other. In general, an individual's beliefs may change relative to a "neighbor" (here neighbor implies a sort of belief close-ness and cultural contact, rather than physical proximity), either towards the neighbor so that their beliefs now conform more closely, or away from the neighbor so that their beliefs now contradict each other more.
Individuals can be said to have power with respect to the appeal of their beliefs. The more powerful an individual, the more likely their neighbors are to use them as their beliefs evolve. When individuals are attached to such a power structure, they tend to form gradients in which everyone within the structure tries to imitate their superior's beliefs, and the belief vector of the group's normal shifts in the direction of its leadership.