In his theory of scientific management, Frederick Winslow Taylor took an early behaviorist approach to motivation. He did not believe that employees had any intrinsic motivation to work, rather that people would only work for rewards (such as pay) or punishments (such as fear of being fired). The human relations approach considered the emotional and social needs of employees. Later organizational psychologists recognized that human motivation is complex. Influenced by Abraham Maslow’s hierarchy of needs, various theorists came up with multifaceted theories of employees’ motivational needs. In 1972, Clayton Alderfer proposed a three-part model of worker motivation: existence needs (basic physical needs), relatedness needs (for social connection and support), and growth needs (for realizing their own potential, similar to Maslow’s self-actualization needs). In 1983, Wofford and Srinivasan suggested that worker performance reflected four factors: competence, motivation, role perception, and the limitations determined by the setting. A manager’s job would be to address each issue as it became relevant.