Another force affected his work: He began his career when the memories of World War II were fresh, and entered into the academic world when the Cold War played a critical role in shaping the United States' political, economic and social atmosphere. Social psychology research added to the knowledge that the United States government and military felt they needed for operating in a new world dynamic (East v. West). For example, the leafleting processes studied by Project Revere were an obvious way to communicate information to a displaced, captive, or isolated population.