Final answer:
The main obstacle to interest group formation is the problem of collective action. This happens because individuals may be reluctant to join or contribute to a group if they believe that their individual efforts will not make a significant impact on the group's success. To overcome this obstacle, interest groups may offer incentives to members or potential members, and external factors can also motivate group mobilization.
Step-by-step explanation:
The main obstacle to interest group formation is the problem of collective action. This happens because individuals may be reluctant to join or contribute to a group if they believe that their individual efforts will not make a significant impact on the group's success. This is known as the free rider problem, where individuals can benefit from the group's efforts without contributing themselves.
To overcome this obstacle, interest groups may offer incentives to members or potential members, such as material benefits or the opportunity to participate in collective action that aligns with their own goals. Groups that are small, well-organized, and have financial resources may also have an advantage in mobilizing and overcoming collective action problems.
Additionally, external factors such as political, social, or economic disturbances can also result in interest group mobilization. When proposed legislation or policies threaten the interests of certain groups, it can motivate them to form or mobilize to protect their interests.