When learning object function, infants must detect relations among featuresfor example, that squeezing is associated with squeaking or that objects with wheels roll. Previously, Perone and Oakes (2006) found 10-month-old infants were sensitive to relations between object appearances and actions, but not to relations between appearances and sounds or actions and sounds. In this article the authors probed the development of infants' attention to feature correlations critical for representing function by testing 8-and 12-month-old infants' (N ¼ 126) sensitivity to such relations. Eight-month-old infants learned individual features but were not sensitive to the relations between those features. Twelve-month-old infants were sensitive to the relation among the features and significantly responded to violations in learned relations between object appearances and actions and between appearances and sounds. Thus, across development, infants become sensitive to an increasing number of relations with age, supporting an information-processing account of the development of object function.Understanding the function of objects is important for learning how to act on and categorize objects. Function is considered central to infants' conceptual development (Keil, 1989;Nelson, 1973Nelson, , 1974Nelson, , 1979), yet there is no standard definition for function in the field of psychological research.Correspondence should be sent to Lisa M. Oakes