Proceedings of the Annual Meeting of the Cognitive Science Society

Whether different formats of numbers are represented by one or more systems across development is a subject of long-standing interest in the field of numerical cognition, with seemingly contradictory results. Here we examined numerical comparison to test a developmental theory that can reconcile these discrepancies. In Experiment 1, we found numerical understanding progresses through three continuous phases of association between numerical symbols and approximate sense of numerosity. In the youngest age group (prefluent phase), comparing numerals were slower than comparing dot arrays, but became similar (fluent phase) then faster (overlearning phase) with age. Because this developmental change occurred in the order of numeric range 1-9, followed by 10-99 and 100-999, multiple phases co-existed during childhood. Furthermore, results from Experiment 2 indicated that comparing different formats of numbers was affected by ratio even at the highest levels of proficiency, suggesting that the approximate number system is never fully replaced.