Trait attribution is central to people's naive theories of people and their actions. Previous developmental research indicates that young children are poor at predicting behaviors from past trait-relevant behaviors. We propose that the cognitive process of behavior-to-behavior predictions consists of two component processes: (1) behavior-to-trait inferences and (2) trait-to-behavior predictions. Experiment 1 demonstrates that 4-, 5-, 7-, and 9-year-olds can infer trait labels from behaviors. Experiment 2 demonstrates that 4-, 5-, and 7-year-olds can predict behaviors from trait labels but not from past behaviors. Experiment 3 demonstrates that 4- and 5-year-olds understand traits as predictive "and" stable over time. Taken together, these three studies show that young children, in possessing component trait-reasoning processes, have a nascent understanding of traits.