Interest articulation is a way for members of a society to express their needs to a system of government. It can range from personal contact with government officials to the development of interest groups (e.g. trade unions, professional associations, religious groups) who act in the interest of larger groups of people. Interest articulation can have different effects in different types of government and can include both legal (i.e.: lobbying, peaceful protest, phone calls and letters to policymakers) and illegal activities (e.g. assassination, riots). Interest articulation leads to interest aggregation. Interest articulation is a way for members of a society to express their needs to a system of government. It can range from personal contact with government officials to the development of interest groups (e.g. trade unions, professional associations, religious groups) who act in the interest of larger groups of people. Interest articulation can have different effects in different types of government and can include both legal (i.e.: lobbying, peaceful protest, phone calls and letters to policymakers) and illegal activities (e.g. assassination, riots). Interest articulation leads to interest aggregation. The types of interest groups, as identified by Gabriel Almond, are: