The ring that does not bind: Topological class in infants’ working memory for objects

Abstract

Infants and adults are highly sensitive to objects' topology (geometrical invariance under stretching). Indeed, topological class information may form the essential core of object representations. We tested this hypothesis by studying 6-month-old infants, who can remember the existence of multiple objects but are limited to remembering the featural identity (e.g. shape or color) of only one object. In two experiments, after hiding two topologically distinct objects separately, we revealed one of the objects to have either changed topology, remained the same, or vanished completely. Bayes Factor analysis showed that infants remembered the topology of only one of the two hidden objects (n=24, Experiment 1), but failed to remember anything about the other object (n=36, Experiment 2). These results contrast with the case of shape and suggest a different, more nuanced role for topological class in infants' object representation.

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.…”

“…Infants’ representations of these objects were examined by removing one of the occluders and revealing either the original hidden object or the unexpected other object, and measuring infants’ looking times to these outcomes. 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).…”

“…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.…”