One reason for the rise of public interest groups in the 1960s and 1970s was

Public interest groups predominantly seek to influence public policy and influence government decisions, and in the 1960s and 1970s, the civil rights and antiwar movements triggered the rise of public interest groups, as a response to unpopular government policies.

In the 1960s and 1970s, the U. S. witnessed a rise of public interest groups, due to the progressive spirit of the time where a good number of them established their offices after 1960 and opened their doors after 1970s. The interest groups comprised of: professional associations, public interest groups, business and agricultural groups, labor groups, ideological groups, and public-sector groups. Several factors determined the growth interest groups in the United States. First, The U. S. is heterogeneous in several aspects: its geography, climate, economic potential, culture, ethnicity, and religions. The heterogeneity resulted in political, socio-economic and cultural divisions which led to the evolution of several interest groups, each with unique objectives.