Conceptually Rich, Perceptually Sparse: Object Representations in 6-Month-Old Infants’ Working Memory

Abstract

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.

Six‐Month‐Old Infants Predict Agents’ Goal‐Directed Actions on Occluded Objects

“…First, infants of this age have previously been shown to successfully infer agents’ goals from their preferential reaching behavior (Luo & Baillargeon, ; Woodward, ) and to make gaze predictions based on agents’ goals (Kim & Song, ; Kochukhova & Gredebäck, ), albeit with some variability (Gredebäck et al., ). Second, and most importantly, 6‐month‐olds’ ability to maintain representations of two occluded objects (in the absence of a social agent) is well understood (Káldy & Leslie, ; Kibbe & Leslie, , , in press). In these studies, infants were familiarized with two featurally distinct objects (e.g., a disk and a triangle) placed sequentially on an otherwise empty stage.…”

“…This method has shown that, when objects are featurally distinct, 6‐month‐old infants represent the featural identity of the object that was hidden last , looking longer when the object is revealed to have changed (Káldy & Leslie, ; Kibbe & Leslie, ). However, 6‐month‐olds consistently fail to remember the featural identity of the object that was hidden first (Káldy & Leslie, ; Kibbe & Leslie, , in press). This robust, frequently replicated signature pattern in 6‐month‐old infants’ ability to represent two sequentially hidden objects can serve as a baseline for us to examine how their representations may be impacted when one of the objects is the target of an agent's goal‐directed reach.…”

“…In our study, we combined the method of Woodward () with that of Kibbe and Leslie (, , in press; Káldy & Leslie, ). Thus, our design deviated from Woodward's () basic design in three respects.…”

“…Thus, our design deviated from Woodward's () basic design in three respects. First, following the design of Kibbe and Leslie (, , in press; Káldy & Leslie, ), on each trial, the two objects (a disk and a triangle) were placed sequentially in front of the agent on an empty stage and then moved sequentially to the back of the stage by an experimenter whose gloved hand was visible to infants. Second, across trials, we counterbalanced the location of the shapes in both familiarization and test so that infants could not form long‐term associations between particular objects and locations (Káldy & Leslie, ; Kibbe & Leslie, , , , in press).…”

“…This measure allowed us to examine what infants encoded or maintained about the features of the objects in the scene. In nonsocial contexts (e.g., Káldy & Leslie, ; Kibbe & Leslie, , , in press), infants show a robust pattern of remembering the features of the last‐hidden object, but not the first‐hidden object, a pattern that emerges from the attentional demands of trying to maintain an object representation (i.e., the first‐hidden object) while tracking and subsequently representing another object (i.e., the last‐hidden object) as it moves into occlusion (Kibbe & Leslie, ; Baillargeon et al., ). Hiding the goal object first allowed us to examine how infants encode objects when the objects’ features are socially relevant.…”