Participants paid one dollar to lie about a boring task later rated it as genuinely more enjoyable than those paid twenty dollars. Why does the smaller payment produce the larger attitude change?

C. Because twenty dollars justifies the lie and one dollar does not.

The result is backwards on any reinforcement account, which is why it mattered. Twenty dollars is an easy explanation for lying, so nothing conflicts; one dollar is not, and the behaviour cannot be undone, so the only movable element is the attitude. It is why effortful initiations increase commitment, and why generous payment to advocate a position rarely converts anyone.