A social psychology term, referring to the practice of soliciting a favor by first asking for something very small you are reasonably sure you can get, such as a signature or a $1 donation. This is followed by asking for a larger favor. The person is more likely to give the larger favor because they feel a sense of obligation after agreeing to the first small favor, or because they feel a sense of guilt for turning down such a small request.

This technique is used often by cults, religions, and political groups in order to slowly escalate demands placed on their adherents.

The Foot-in-door technique has also been called the Graduation technique. It is the opposite of the Door-in-the-face technique. It is one of the three Compliance Traps, along with Door-in-the-face technique and Low ball technique.

Influence: The Psychology of Persuasion by Robert B. Cialdini