The development of object representations in children.

Objects in scenes follow a hierarchical organization, with "scenes" at the top level, followed by "phrases", clusters of objects that share spatial and functional proximity. Within these phrases, "anchor" objects help predict the identity and location of smaller, dependent "local" objects. Previous research has shown that this hierarchy is reflected in the mental representations of objects in adults. The current study examined whether children's object representations already reflect this hierarchy. We implemented an odd-one-out task with 36 object images to collect pairwise similarity ratings from children ages 5 to 10 years. Two different groups of children received different similarity judgment instructions: One group received no explicit definition of similarity, but the other was told to base similarity on actions typically performed with the objects. We created a priori and data-driven scene hierarchy measures to evaluate how well they aligned with children's similarity judgments. Results showed that children's representations were clearly structured at the scene level, as indicated by strong effects in both hierarchy measures. In contrast, we found no reliable phrase-level effects and only a small data-driven object-type effect. Scene-level structure strengthened with age, whereas phrase- and object-type levels showed no reliable age-related change. Importantly, similarity patterns were highly comparable across both tasks, suggesting that children's object representations by default seem to be action based. These results suggest that children organize objects along the scene level of the hierarchy incorporating actions related to the objects in their representations, whereas finer-grained relations are more weakly represented and may be more difficult to detect reliably at this age.