In this chapter, the author suggests that to understand individuals' motivation to learn about and engage in a particular activity on their own initiative (i.e., presumably intrinsically motivated behavior), one must focus on individual interest. Individual interest increases as knowledge and the accompanying value of the subject increases, and she suggests that it is individual interest that sustains attention and effort. She discusses how individual interest may develop over time, how this development can be supported by a child's environment, and how individual interest may vary both within and across individuals as a function of gender, age, and atypical development (e.g., particular learning disabilities or syndromes). (PsycInfo Database Record (c) 2020 APA, all rights reserved)