Final answer:
Marie wants to conform to her friends' choice in mp3 players, which is influenced by conformity, a behavior driven by the desire to fit in and be accepted by a social group.
Step-by-step explanation:
The term that best describes why Marie only wants a certain brand of mp3 player to fit in with her friends is conformity. Conformity is the act of matching attitudes, beliefs, and behaviors to what individuals perceive is normal within their group or society. Advertising techniques, such as the bandwagon fallacy, often capitalize on the human desire for conformity, suggesting that buying a certain product will help individuals fit in or be accepted by a group.
Young individuals, like high school students, are particularly influenced by normative social influence—the pressure to conform in order to be accepted or liked by their friends and peers. This influence is a strong factor in consumer decisions, as marketers are aware that many people want to own what is considered popular or in trend to maintain a social standing with their peers.