How Much Do You Remember When It's up to You? Measuring Memory Use Without Response Bias in Young Children

Outside the laboratory, people tend not to push working memory to its limits. Instead, we tend to capitalize on stable, external resources (e.g., assembly diagrams or shopping lists) in a dynamic, context-dependent trade-off with internal memory: we sample the environment more when remembering is "costly" (e.g., when a shopping list is difficult to remember) and remember more when sampling is costly (e.g. when the list is difficult to access). Here, we used our gamified Shopping Game paradigm to characterize this sampling-remembering trade-off in preschoolers (the youngest age at which it has been tested). In two preregistered experiments, 157 children (Exp. 1: 82 4.5-7-year-olds; Exp. 2: 75 5.5-7-year-olds, from the Northeastern US) used a touchscreen tablet to pick items from a virtual store based on a shopping list. Children could not see the list and store simultaneously, but could toggle between them. When we introduced a cost to access the list (a 4 s lag before it appeared), children accessed it less, instead opting to remember more on each trip (but still less than their maximal capacity). In Experiment 1, we determined that children begin to respond to these costs at around 5.8 years of age. In Experiment 2, we showed that children exhausted the contents of their memory on each of their visits to the store: when it's up to them, young children seem to only load up their memory with as much as they intend to use. A video abstract of this article can be viewed at https://youtu.be/ZfJkod0Vj3k. SUMMARY: Here, we used our novel, gamified 'Shopping Game' paradigm to measure naturalistic memory use in 4.5-7-year-old children. Crucially, we could contrast how much a child could remember, how much they chose to remember, and how much of what was remembered was applied. We found that children will take advantage of an external resource (a shopping list) more and remember less, as the cost to access them decreases. This cost-dependent trade-off between sampling and remembering emerges around 5.8 years of age in our task.