Children exhibit superior memory for attended but outdated information compared to adults

Human cognitive resources are limited, necessitating information selection for efficient processing. Selective attention, the primary mechanism for prioritizing relevant information, matures gradually from childhood to adulthood. While adults excel at processing task-relevant information, children often outperform adults in processing task-irrelevant information. This study explores another facet of cognitive selectivity—memory selection—which refers to the brain's ability to filter out attended but outdated information that is no longer needed for the current task. This process is distinct from attentional selection, as it involves a post-attentional selection of information for memory encoding and retention. Traditional views propose attention as the gateway to working memory; however, recent attribute amnesia studies challenge this by demonstrating that even fully attended information can be excluded from working memory. This suggests a re-selection process within working memory—memory selection—that filters out attended but irrelevant information. While the development of attentional selection is extensively studied, the development of memory selection remains largely unexplored. This study directly investigates this gap by comparing the memory selection abilities of young children and adults using the attribute amnesia paradigm. The paradigm exploits the fact that participants must attend to a key feature (e.g., the identity of a target letter) to perform a task, but this feature is not necessary for the task's primary goal (e.g., reporting the location of the letter). The performance difference in recalling this key feature between children and adults will reflect their differing memory selection abilities, rather than differences in attentional selection.

Extensive research exists on the development of selective attention, showing that the ability to focus on relevant information and filter out distractions improves significantly from infancy to adulthood. Infants and young children often struggle to concentrate and filter out distractions, but their abilities improve with age. However, studies consistently demonstrate that children outperform adults in processing task-irrelevant information. This seemingly paradoxical finding has led to the investigation of distinct mechanisms of cognitive selectivity. This study builds upon previous research on attentional selection and introduces the concept of memory selection to explain the observed developmental differences in information processing and retention.

Five experiments were conducted to compare the memory selection abilities of children and adults (approximately 130 children and 130 adults in total). The experiments used the attribute amnesia paradigm, requiring participants to perform a location task where they needed to identify a target (letter or animal picture) among distractors. In a surprise test following the main task, participants were unexpectedly asked to recall the identity of the target (the key feature). Experiment 1 used English letters as targets and Arabic numbers as distractors. Experiment 2 used highly familiar animal pictures to rule out the possibility that the results were due to stimulus familiarity. Experiment 3 used a number comparison task to ensure both groups processed the target's identity. Experiment 4 utilized eye-tracking technology to directly compare attention allocation between the groups. Experiment 5 replicated the findings using a larger sample size. The experiments varied the stimulus type (letters, pictures, numbers), stimulus presentation time (250ms, 1000ms), and response method (key press, verbal response) to control for potential confounding variables. Adult participants were recruited from Zhejiang University, and children were recruited from a kindergarten in Hangzhou, China. Data analysis involved statistical tests such as t-tests, z-tests, ANOVAs, and chi-squared tests, along with the calculation of Bayes factors to evaluate the evidence supporting null hypotheses. Eye movement data in Experiment 4 was analyzed by considering the proportion of fixation duration on the target and distractor areas.

Across all five experiments, children consistently showed significantly better memory for the attended but outdated target identity (key feature) in the surprise test compared to adults. Experiment 1 revealed that children (80% correct) outperformed adults (50% correct) in recalling the target letter's identity. Experiment 2 replicated this finding using familiar animal pictures, with children achieving 85% accuracy compared to 55% for adults. Experiment 3 ruled out alternative explanations regarding categorization strategies and response methods, showing similar results. Experiment 4, using eye-tracking, demonstrated that while adults allocated more attention to the target, they still performed worse than children in recalling the key feature, suggesting that attentional allocation alone did not account for the results. Experiment 5, with a larger sample size (50 participants per group), replicated the main finding, with children (86% correct) significantly outperforming adults (46% correct). Furthermore, children showed a greater disruption of location memory in the surprise trial than adults, suggesting greater interference to their working memory storage by unexpected events. The consistent results across different experiments and sample sizes strongly suggest a developmental difference in memory selection, rather than methodological artifacts.

The findings demonstrate a developmental reversal in memory selection, where children exhibit superior memory for attended but outdated information compared to adults. This challenges the common assumption that children's weaker attentional selectivity leads to their better memory for task-irrelevant information. The results support the hypothesis that children's weaker memory selection, not attentional differences, accounts for this phenomenon. The underdevelopment of memory selection in children might be due to their immature inhibitory control, hindering their ability to efficiently filter out attended but unnecessary information from entering working memory. This is consistent with research showing that children have underdeveloped inhibitory processes affecting intentional forgetting. While the over-retention of outdated information might seem maladaptive, it could serve an adaptive function for learning by facilitating broader exploration and sequential pattern identification in children's learning. Further research is needed to investigate the interplay between attentional selection, memory selection, and inhibitory control in cognitive development.

This study provides strong evidence for a developmental reversal in memory selection, showing that children retain attended but outdated information more effectively than adults. This highlights the importance of considering memory selection in understanding cognitive development, particularly the interplay between attention, working memory, and inhibitory control. Future research should explore the underlying mechanisms of memory selection and its implications for learning and memory development across the lifespan. This includes investigating the relationship between memory selection and other cognitive abilities, such as inhibitory control, and exploring the potential adaptive functions of retaining outdated information in children's learning.

While the study employed rigorous methodology and multiple experiments, certain limitations exist. The convenience sampling method may limit the generalizability of the findings. The reliance on behavioral measures, while effective in demonstrating the core phenomena, does not provide direct insights into the underlying neural mechanisms of memory selection. Future research using neuroimaging techniques could provide a deeper understanding of the brain processes involved. Finally, while this study shows a difference in memory selection between children and adults, the specific age range at which this developmental process matures warrants further investigation. It is important to note the cross-sectional nature of the study and the need for longitudinal studies to track memory selection development more precisely.