Abraham Maslow is known for establishing the theory of a hierarchy of needs, writing that human beings are motivated by unsatisfied needs, and that certain lower needs need to be satisfied before higher needs can be satisfied. Maslow studied exemplary people such as Albert Einstein, Jane Addams, Eleanor Roosevelt, and Frederick Douglas rather than mentally ill or neurotic people. This was a radical departure from two of the chief schools of psychology of his day: Freud and B.F. Skinner. Freud saw little difference between the motivations of humans and animals. We are supposedly rational beings; however, we do not act that way. Such pessimism, Maslow believed, was the result of Freud's study of mentally ill people. "The study of crippled, stunted, immature, and unhealthy specimens can yield only a cripple psychology and a cripple philosophy" (Motivation and Personality). Skinner, on the other hand, studied how pigeons and white rats learn. His motivational models were based on simple rewards such as food and water, sex, and avoidance of pain. Say "sit" to your dog and give the dog a treat when it sits, and-after several repetitions--the dog will sit when you command it to do so. Maslow thought that psychologists should instead study the playfulness, affection, etc., of animals. He also believed that Skinner discounted things that make humans different from each other. Instead, Skinner relied on statistical descriptions of people. Maslow's hierarchy of needs was an alternative to the depressing determinism of Freud and Skinner. He felt that people are basically trustworthy, self-protecting, and self-governing. Humans tend toward growth and love. Although there is a continuous cycle of human wars, murder, deceit, etc., he believed that violence is not what human nature is meant to be like. Violence and other evils occur when human needs are thwarted. In other words,