What does the foot-in-the-door phenomenon predict about participants agreeing to a larger request after a smaller one?

The foot-in-the-door phenomenon refers to the psychological tendency where individuals who agree to a small initial request are more likely to comply with a larger request later on. This occurs because the initial agreement often leads to a change in self-perception, where individuals see themselves as helpful or cooperative. Once they have committed to a small action, they are more likely to follow through with a larger request due to the desire to maintain consistency with their previous behavior.

In the context of the question, when participants first agree to take part in a study, their initial commitment can enhance their willingness to comply with a subsequent, larger request related to that study, such as undergoing a medical test. This concept is widely used in persuasion strategies, highlighting how small commitments can lead to more significant agreements, reinforcing the importance of initial compliance in fostering greater involvement or participation in later actions.