Final answer:
The result of members joining a group for different reasons ranges from unity in purpose to challenges like division and lack of cohesion; leaders sustain group activity by offering incentives and fostering belonging.
Step-by-step explanation:
When members join a group for different reasons, it is likely to result in a variety of outcomes based on the incentives and the size of the group. Individuals join groups due to various incentives like purposive incentives, solidary incentives, and material incentives. Groups formed due to shared interests, despite different underlying reasons, might be motivated by a common goal, such as legal music downloading, to come together and form organizations like the Future of Music Coalition.
However, as these groups grow larger, they could face challenges such as division and lack of cohesion, which are common in large, broad-based movements like fraternities or global organizations. On the other hand, leaders play a key role in maintaining group activity and unity by offering different types of incentives, addressing collective action problems, and fostering a sense of belonging, which can be crucial for sustaining membership and achieving group objectives.