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

• Both infants and adults are highly sensitive to objects’ topological class.
• We asked whether topology is therefore an essential part of object representations.
• We tested 6-month-olds’ working memory for two topologically distinct objects.
• Infants remembered the topology of one object, and nothing about the other.
• Results suggest a more nuanced role for topology in infants’ object representations.

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.