Albert Bandura, a Stanford University psychology professor, has been awarded the 2008 Louisville Grawemeyer Award for Psychology, which includes a $200,000 prize.
The Grawemeyer Foundation is based at the University of Louisville.
The judges said that Bandura's ideas have helped other psychologists understand human behavior.
"He has had enormous impact not only on psychology but on other disciplines as well," the award committee stated.
Bandura has shown that a belief in one's capabilities affects the tasks that people choose, how much effort is put into them and how people feel about doing them.
A 2002 survey in the Review of General Psychology ranked Bandura as the fourth most eminent psychologist of the 20th century behind B.F. Skinner, Jean Piaget and Sigmund Freud.