Carol Dweck has investigated what people believe about themselves and how this affects their motivation, and their ability to accomplish tasks, achieve goals, and function successfully in life. She proposes, that people tend to have two extremes of belief about themselves, that are the key to their effectiveness or ineffectiveness. One extreme is of a self that is an unchanging entity and the other extreme is of a self that is constantly changing in varying increments. Dweck asserts that one theory is highly adaptive for the human condition (the theory of an incremental changing self) while the other is maladaptive for the human condition (the theory of a self that is an unchanging entity). These self theories can be termed respectively a growth mindset and a fixed mindset. This applies regardless of whether the motivation is intrinsic or extrinsic. Although, people with an extrinsic orientation tend to have a fixed mindset, and people who have an intrinsic orientation tend to have a growth mindset.