Tracking what went where across toddlerhood: Feature-location bound object representations in 2- to 3-year-olds' working memory.

Two experiments examined the development of the ability to encode, maintain, and update integrated representations of occluded objects' locations and featural identities in working memory across toddlerhood. Sixty-eight 28- to 40-month-old US toddlers (13 Asian or Pacific Islander, 6 Black, 48 White, 1 multiracial; 40 girls; tested between February 2015 and July 2017) tracked the locations of different color beads that were hidden simultaneously (Experiment 1) or sequentially (Experiment 2). Toddlers' ability to reliably store feature-location bound object representations in working memory varied as a function of age, memory load, and task demands. These results bridge a developmental gap between infancy and early childhood and provide new insights into sources of limitation and developmental change in children's early object representational capacities.

Children's understanding of economic demand: A dissociation between inference and choice.

Adults infer that resources that become scarce over time are in higher demand, and use this "demand inference" to guide their own economic decisions. However, it is unclear when children begin to understand and use economic demand. In six experiments, we investigated the development of demand inference and demand-based economic decisions in 4- to 10-year-old children and adults in the United States. In Experiments 1-5, we showed children two boxes with the same number of compartments but containing different numbers of face-down stickers and varied the information provided about how those differences arose (e.g. that other children had taken the stickers). In separate experiments, we asked children to buy or trade to get a sticker for themselves or to predict what other children would do. We also asked them which set of stickers they thought the other children had preferred to assess their ability to make a demand inference separately from their own choice. Across experiments, children were able to make a demand inference about children's past preferences by 6 years of age. However, children did not use this demand information when making choices for themselves or when predicting what another child would select in the future. In Experiment 6, we adapted the task for adults and found that adult participants inferred that the set containing fewer resources was in higher demand, and selected the higher demand resource for themselves at rates significantly above chance. The overall pattern of results suggests a dissociation between economic inference and economic decisions during early-to-middle childhood. We discuss implications for our understanding of the development of economic reasoning.

Young children monitor the fidelity of visual working memory.

The ability to concurrently maintain representations of multiple objects and their locations in visual working memory is severely limited. Thus, making optimal use of visual working memory requires continual, moment-to-moment monitoring of its fidelity: High-fidelity representations can be relied upon, whereas incomplete or fuzzy representations must be refreshed or ignored. Previous work showed that adults track the fidelity of their visual working memory. Here, we asked whether children, whose capacities for visual working memory are undergoing protracted development, also can do so. We showed 5- and 6-year-olds sets of 2-5 single-feature (Experiment 1) or multifeature (Experiment 2) objects hidden simultaneously in separate locations. We asked children to recall the location of one of the objects, then bet 0-3 resources on whether they were correct. In both experiments, we found that children's confidence in their visual working memory, as indexed by their bets, was correlated with their accuracy on each trial, controlling for task difficulty: Children bet higher when they were correct and lower when they were incorrect. Our results suggest that metacognitive awareness of the representational limits of visual working memory may emerge before working memory reaches stable capacity. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Six-Month-Old Infants Predict Agents' Goal-Directed Actions on Occluded Objects.

Infants can infer agents' goals after observing agents' goal-directed actions on objects and can subsequently make predictions about how agents will act on objects in the future. We investigated the representations supporting these predictions. We familiarized 6-month-old infants to an agent who preferentially reached for one of two featurally distinct objects following a cue. At test, the objects were sequentially occluded from the infant in the agent's presence. We asked whether infants could generate action predictions without visual access to the relevant objects by measuring whether infants shifted their gaze to the location of the agent's hidden goal object following the cue. We also examined what infants represented about the hidden objects by removing one of the occluders to reveal either the original hidden object or the unexpected other object and measuring infants' looking time. We found that, even without visual access to the objects, infants made predictive gazes to the location of the agent's occluded goal object, but failed to represent the features of either hidden object. These results suggest that infants make goal-based action predictions when the relevant objects in the scene are occluded, but doing so may come at the expense of maintaining representations of the objects.