Angela Duckworth is a professor of psychology who used to teach mathematics to children. While she was teaching, Duckworth noticed that the intelligence and natural talent of her students were not necessarily correlated with success in test-taking. Instead, those students who reached the top of the class shared a quality which she identified as "grit," a mixture of passion for learning and perseverance in mastering the subject.
This insight led Duckworth to conduct the research that formed the basis for her book Grit: The Power of Passion and Perseverance. She observed people in challenging situations, from cadets at West Point Military Academy to children competing in the National Spelling Bee. She also interviewed high achievers in a variety of areas from finance to sports. In all cases, she found that the same combination of qualities were critical to their success.
Duckworth's conclusion, therefore, is that grit is a vital and underappreciated quality which is one of the principal ingredients for success in life. It is more closely correlated with high achievement than intellect, intelligence, empathy, attractiveness, or various other qualities which have been examined by social psychologists. Moreover, Duckworth contends that grit is a quality which is not simply fixed and innate, but which can be learned and developed through practice.