An interest group is a group of individuals who share common objectives, and whose aim is to influence policymakers. Institutional interests are organizations that represent other organizations, whose rules and policies are custom-fit to the needs and wants of the organizations they serve. This includes the American Cotton Manufacturers (which represents the generally congruous southern textile mills) and the U.S. Chamber of Commerce (which represents the multitude of wants of American businesses).
Membership interests are organizations that represent individuals for social, business, labor, or charitable purposes, in order to achieve civil or political goals. This includes the NAACP(represents African-American interests), the Sierra Club (represents environmental interests), the NRA (represents Second Amendment interests, Figure 1), and Common Cause (represents interests in an increase in voter turnout and knowledge). Membership includes a group of people that join an interest group and unite under one cause. They may or may not have an opinion on some of the issues the staff pursues. Similarly, staff are the leaders of this group that heads up the membership. With the membership united under one cause, the staff has the ability to pursue other issues that the membership may disagree on, but will remain members united by the primary cause.
Benefits and Incentives
The general theory is that individuals must be enticed with some type of benefit to join an interest group. Known as the free rider problem, it refers to the difficulty of obtaining members of a particular interest group when the benefits are already reaped without membership. For instance, an interest group dedicated to improving farming standards will fight for the general goal of improving farming for every farmer, even those who are not members of that particular interest group. Thus, there is no real incentive to join an interest group and pay dues if the farmer will receive that benefit anyway. Interest groups must receive dues and contributions from its members in order to accomplish its agenda. While every individual in the world would benefit from a cleaner environment, an Environmental protection interest group does not, in turn, receive monetary help from every individual in the world.
Selective material benefits are benefits that are usually given in monetary benefits. For instance, if an interest group gives a material benefit to their member, they could give them travel discounts, free meals at certain restaurants, or free subscriptions to magazines, newspapers, or journals. Many trade and professional interest groups tend to give these types of benefits to their members. A selective solidary benefit is another type of benefit offered to members or prospective members of an interest group. These incentives involve benefits like "socializing congeniality, the sense of group membership and identification, the status resulting from membership, fun and conviviality, the maintenance of social distinctions, and so on. A solidary incentive is one in which the rewards for participation are socially derived and created out of the act of association.
An expressive incentive is another basic type of incentive or benefit offered to being a member of an interest group. People who join an interest group because of expressive benefits likely joined to express an ideological or moral value that they believe in. Some include free speech, civil rights, economic justice, or political equality. To obtain these types of benefits, members would simply pay dues, donating their time or money to get a feeling of satisfaction from expressing a political value. Also, it would not matter if the interest group achieved their goal; these members would merely be able to say they helped out in the process of trying to obtain these goals, which is the expressive incentive that they got in the first place. The types of interest groups that rely on expressive benefits or incentives would be environmental groups and groups who claim to be lobbying for the public interest.
Mancur Lloyd Olson, a leading American economist, sought to understand the logical basis of interest group membership and participation. The reigning political theories of his day granted groups an almost primordial status. Some appealed to a natural human instinct for herding, others ascribed the formation of groups that are rooted in kinship to the process of modernization. Olson offered a radically different account of the logical basis of organized collective action. In his first book, The Logic of Collective Action: Public Goods and the Theory of Groups (1965), he theorized that “only a separate and ‘selective’ incentive will stimulate a rational individual in a latent group to act in a group-oriented way”; that is, members of a large group will not act in the group's common interest unless motivated by personal gains.