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Six-month-old infants can store representations of multiple objects in working memory but do not always remember the objects' features (e.g., shape). Here, we asked whether infants' object representations (a) may contain conceptual content and (b) may contain this content even if perceptual features are forgotten. We hid two conceptually distinct objects (a humanlike doll and a nonhuman ball) one at a time in two separate locations and then tested infants' memory for the first-hidden object by revealing either the original hidden object or an unexpected other object. Using looking time, we found that infants remembered the categorical identity of the hidden object but failed to remember its perceptual identity. Our results suggest that young infants may encode conceptual category in a representation of an occluded object, even when perceptual features are lost.

How distinct are visual memory representations from visual perception? Although evidence suggests that briefly remembered stimuli are represented within early visual cortices, the degree to which these memory traces resemble true visual representations remains something of a mystery. Here, we tested whether both visual memory and perception succumb to a seemingly ubiquitous neural computation: normalization. Observers were asked to remember the contrast of visual stimuli, which were pitted against each other to promote normalization either in perception or in visual memory. Our results revealed robust normalization between visual representations in perception, yet no signature of normalization occurring between working memory stores-neither between representations in memory nor between memory representations and visual inputs. These results provide unique insight into the nature of visual memory representations, illustrating that visual memory representations follow a different set of computational rules, bypassing normalization, a canonical visual computation.

What does an infant remember about a forgotten object? Although at age 6 months, infants can keep track of up to three hidden objects, they can remember the featural identity of only one. When infants forget the identity of an object, do they forget the object entirely, or do they retain an inkling of it? In a looking-time study, we familiarized 6-month-olds with a disk and a triangle placed on opposite sides of a stage. During test trials, we hid the objects one at a time behind different screens, and after hiding the second object, we removed the screen where the first object had been hidden. Infants then saw the expected object, the unexpected other object, or the empty stage. Bayes factor analysis showed that although the infants did not notice when the object changed shape, they were surprised when it vanished. This finding indicates that infants can represent an object without its features.