Influence: The Psychology of Persuasion

by Robert B. Cialdini

Psychologists have long recognized a desire in most people to be and look consistent within their words, beliefs, attitudes, and deeds. This tendency for consistency is fed from three sources. First, good personal consistency is highly valued by society. Second, aside from its effect on public image, generally consistent conduct provides a beneficial approach to daily life. Third, a consistent orientation affords a valuable shortcut through the complexity of modern existence. By being consistent with earlier decisions, one reduces the need to process all the relevant information in future similar situations; instead, one merely needs to recall the earlier decision and to respond consistently with it. Within the realm of compliance, securing an initial commitment is the key. After making a commitment (that is, taking an action, stand, or position), people are more willing to agree to requests in keeping with the prior commitment. Thus, many compliance professionals try to induce people to take an initial position that is consistent with a behavior they will later request from these people. Not all commitments are equally effective in producing consistent future action. Commitments are most effective when they are active, public, effortful, and viewed as internally motivated (voluntary), because each of these elements changes self-image. The reason they do so is that each element gives us information about what we must truly believe. Commitment decisions, even erroneous ones...