Final answer:
The foot-in-the-door phenomenon is the tendency for people to agree with a larger request after first agreeing to a smaller one.
Step-by-step explanation:
The tendency for people who have first agreed to a small request to comply later with a larger request is called the foot-in-the-door phenomenon. This technique involves persuading someone to agree to a small favor or purchase a small item before asking for a bigger favor or a more expensive purchase. For example, a salesperson may convince a customer to buy a low-cost accessory first before suggesting a more expensive product. Once the person has committed to the initial request, they are more likely to comply with the larger request.