Maslow based his theory partially on his own assumptions about human potential and partially on his case studies of historical figures whom he believed to be self-actualized, including Albert Einstein and Henry David Thoreau. Consequently, Maslow argued, the way in which essential needs are fulfilled is just as important as the needs themselves. Together, these define the human experience. To the extent a person finds cooperative social fulfillment, he establishes meaningful relationships with other people and the larger world. In other words, he establishes meaningful connections to an external reality—an essential component of self-actualization. In contrast, to the extent that vital needs find selfish and competitive fulfillment, a person acquires hostile emotions and limited external relationships—his awareness remains internal and limited.