Recent research has suggested that young children have relatively well-developed trait concepts. However, this literature overlooks potential age-related differences in children's appreciation of the fundamentally dimensional nature of traits. In Study I, we presented 4-, 5-, and 7-year-old children and adults with sets of characters and asked them to indicate the preferences of a target character who shared appearance attributes with one character (appearance match) and shared a common trait with the other character (trait match). Traits were presented in a way that emphasized either their categorical or their dimensional nature. When the dimensional nature of trait terms was emphasized, the youngest children made fewer trait-based inferences, and the use of traits increased with age. In Study 2, we gave 4-year-old children and adults the same task except that the extent to which appearance cues could serve as a meaningful basis of judgment was varied. Results were consistent with the findings of Study I, although children were more likely to rely on dimensional presentations of traits in the absence of strong appearance cues.
Gonzalez, Celia M., Kristina M. Zosuls, and Diane N. Ruble. "Traits as Dimensions or Categories? Developmental Change in the Understanding of Trait Terms." Developmental Psychology 46.5 (September 2010): 1078-1088.