Conformity is reinforced within the group. Members feel more secure when someone gives their testimony, when doctrines and beliefs are repeated. Self-criticism is encouraged, individual differences discouraged. Expressing doubts or ideas that are unorthodox usually means punishment of some kind, from silence to criticism to outright ostracism. This group approval or disapproval is powerful enough to manipulate behavior. Especially for those who are attracted to the social support of a religion, the threat of shame is an effective deterrent for any deviance.