Infants' integration of featural and numerical information.

The current study examined the integration of non-numerical (featural) and numerical information in 9-, 11-, and 13-month-old infants’ performance on a number discrimination task. Infants were habituated to pictures of objects (e.g., bowl, shoe) either in groups of two or three. In the test phase, infants saw both new and old objects in both groups of two and three. Nine-month-old infants discriminated number independent of the familiarity of the object, 11-month-old infants discriminated between familiar and novel objects (but not the number of objects), and 13-month-old infants discriminated between the familiar and novel objects only in the context of a familiar number of objects. These data suggest that early number representations are dissociated from featural information, and that the integration of these stimulus properties is a developmental process that occurs across the first year.