Expertise

Expertise is the accrual of domain-specific knowledge through experience. In the view presented here, expertise is not absolute (e.g., 10,000 hours of practice) but rather relative. People gain expertise via formal education, informal learning from others, practical experience, or exploration. Because additional experiences can result in additional expertise, accumulation of expertise can continue across the life span. This entry focuses on conceptual effects of expertise, showing how expertise leads to changes in conceptual organization (i.e., how we organize what we know) and reasoning (i.e., how we use what we know to make guesses about what we don’t know) and how, perhaps surprisingly, the effects of gaining expertise are remarkably similar across the life span.