Final answer:
The principle of influence at work for offering a free t-shirt and water bottle to encourage walkathon participation is reciprocity. This creates a sense of indebtedness that can motivate people to participate, aligning with our tendency to return favors and influence ideas and behaviors.
Step-by-step explanation:
The principle of influence being used in the scenario is reciprocity. By offering a free t-shirt and water bottle, the organization is giving a gift to the participants, which can create a sense of indebtedness leading to an increased likelihood of participation. This approach plays on the natural human tendency to want to return favors and is a well-documented strategy in encouraging people's attitude, ideas, and behaviors.
The foot-in-the-door technique is another related concept in social psychology, where a persuader gets someone to agree to a small request before making a larger one. The initial commitment engages the principle of consistency, as people prefer to act consistently with their past behavior. However, in the context of the walkathon, the primary strategy is reciprocity rather than consistency or the foot-in-the-door technique.