You planned to buy a dress, not a purse. But you bought a purse because the salesperson said, "You really need a purse that matches your new dress."
You're feeling the power of consistency when you go along with a suggestion automatically.
Robert Cialdini calls consistency a "shield against thought" that protects us from "unpleasant realizations" (such as the fact that you can hardly afford the new dress).
We prize consistency because we think inconsistency is a character flaw. But that belief can work against our interests.
Consistency kicks in after commitment.
You feel the power of commitment whenever you accept a suggestion to extend your involvement after saying "yes" to a simple request.
- You agree to take your utility company's phone survey, then agree to switch to a more expensive monthly plan.
- You agree to sign a petition, then agree to donate to the cause.
- You agree to attend a free seminar, then buy an annuity.
Commitment rules us because it affects self-image. We want to be smart consumers, good citizens, shrewd investors. But that belief can also work against our interests.
Consistency and commitment explain why contests generate new customers; why "lowball" pricing produces profits; and why cross-selling is part of every salesperson's skill-set.
Want to persuade someone? Ask him to perform an easy deed.