On the functional independence of the approximate number system and visual working memory in infants

Understanding the developmental origins of cognitive systems provides critical insight into the broader landscape of human cognitive abilities. The relationship between Visual Working Memory (VWM) and the Approximate Number System (ANS) in early infancy has remained largely underexplored, despite adult studies suggesting these systems operate as functionally independent stages of information processing. This study investigates VWM span and the acuity of ANS in infants aged 9-12 months, aiming to determine if individual VWM span correlates with ANS acuity in this age group. A cohort of 14 infants was assessed through a series of visual change detection tasks with varying set sizes (1, 2, 3, and 4 elements) and numerical ratios (1:2, 2:3 and 3:4). Preference scores were derived from looking times, and correlations between VWM and ANS performance were analyzed. In the VWM tasks, infants exhibited a significant preference for changes in set sizes of 1 and 2 elements, indicating a VWM span of up to 2 elements. No significant preference was observed for larger set sizes. No significant preference was measured for numerical change, at any given ratio The lack of correlation between VWM and ANS supports the hypothesis of their functional independence, suggesting distinct developmental origins for these systems. Nevertheless, Bayesian correlation analyses provided insufficient evidence for either the presence or the absence of a significant correlation, highlighting the need for further research to substantiate these findings. These findings advance our understanding of early cognitive development and clarify the nature of number sense and its integration into complex cognitive architecture. However, the small sample size limits the generalizability of these findings, underscoring the need for further investigation to confirm these results.