New evidence for rapid development of color-location binding in infants' visual short-term memory

Change-detection tasks reveal that infants' ability to bind color to location in visual short-term memory (VSTM) develops rapidly: Seven-month-old infants, but not 6-month-old infants, detect that successive arrays of 3 objects are different if they contain the same colors in different locations (Oakes et al., 2006). Here we test a counterintuitive consequence of the hypothesis that six-month-old infants are unable to bind colors to locations: When comparing two successive stimulus arrays, these infants will often compare noncorresponding items, making it impossible for them to distinguish between identical arrays and nonidentical arrays. As a result, they will not show a preference for changing arrays over nonchanging arrays even when all of the items change. We tested this prediction by presenting 6- and 7-month-old infants (N = 36) with nonchanging displays of three items and changing displays in which all three items simultaneoulsy changed colors. As predicted, 7-month-old infants, but not 6-month-old infants, responded to the difference between these changing and nonchanging displays, providing additional evidence that the ability to bind colors to locations develops rapidly across this age range.