David McClelland was a well-known Harvard professor who had been researching at the university for over thirty years. His research focused primarily on human motivation, but he also studied personalities in a broader sense (Johnson et al, 2018). This theory is also known as, The three social motives or Acquired Need Theory (Reduan, 2015).
According to the theory, three basic desires influence everyone's motivation. A person's motivation is driven by a desire for power, accomplishment, and affiliation. These needs are scalar, and everyone has a mix of them, though one is usually dominant. (Johnson et al, 2018). Everyone is more strongly motivated by some needs and less strongly motivated by others. He also stated that everyone has all three of these motives, albeit to varying degrees, and that the result of the needs is a unique mix that gives one's personality (McClelland, 1987).
McClelland’s theory of needs is based on three types of needs. They are described below.