Objectives <p>Category learning involves learning group items based on similar feature values, and it is a key ability that allows us to acquire new concepts and skills throughout our lives. Yet we know little about the traits and situational factors that facilitate category learning and how those differ in older age. Here, we test the relationship between categorization performance and individual differences in a variety of cognitive abilities and aspects of state of mind and how those relationships differ in older age.</p> Method <p>Seventy-six young adults (18–29 years old) and 73 older adults (60–83 years old) underwent a cognitive assessment testing processing speed, working memory, verbal comprehension, and perceptual reasoning. Two categorization sessions followed where participants completed a categorization task and state of mind questionnaires assessing stress, motivation, mood, and sleep.</p> Results <p>An individual’s cognitive abilities were significant positive predictors of categorization test accuracy. This effect was not moderated by age groups. Most state of mind variables were not significant predictors of categorization test accuracy, except that young adults with negative mood performed worse on the categorization test compared to older adults.</p> Discussion <p>We show that baseline cognitive abilities influence categorization test accuracy more than state of mind variables regardless of age. Thus, interventions may be most effective when they are designed to work with individual’s existing knowledge rather than attempt to directly manipulate transient states of mind.</p>