In two experiments, we examined the role of labels in guiding preschoolers' extension of three types of familiar adjectives: emotional state adjectives, physiological state adjectives, and trait adjectives. On each trial, we labeled a target animal with one of the three different types of adjectives and asked whether these terms could apply to a subordinate-level match, a basic-level match, a superordinate-level match, or an inanimate object. In Experiment 1, participants extended trait adjectives, but not emotional or physiological adjectives, to members of the same basic-level category, regardless of whether an explicit basic-level label was provided for the target animal. Similarly, children in Experiment 2 also extended trait adjectives to the members of the same basic-level category, even when explicit superordinate- and subordinate-level labels were provided for the target animals. Together, these results demonstrate that children appreciate that emotional and physiological adjectives cannot be generalized to the same extent as can trait adjectives, and the results document the privileged status of basic-level categories in preschoolers' extension of trait adjectives.