Your motivations--get that promotion, throw the best parties, run for public office--aren't impersonal abstractions but powerfully reflect who you are and what you focus on. An individual's goals figure prominently in the theories of personality first developed by the Harvard psychologist Henry Murray. According to his successor David McClelland, what Friedrich Nietzsche called "the will to power," which he considered the major driving force behind human behavior, is one of the three basic motivations, along with achievement and affiliation, that differentiate us as individuals.

A simple experiment show show these broad emotional motivations can affect what you pay attention to or ignore on very basic levels. When they examine images of faces that express different kinds of emotion, power-oriented subjects are drawn to nonconfrontational visages, such as "surprise faces," rather than to those that suggest dominance, as "anger faces" do. In contrast, people spurred by affiliation gravitate toward friendly or joyful faces.

Winifred Gallagher