Parallel individuation supports numerical comparisons in preschoolers

Pierina Cheung,Mathieu Le Corre

doi:10.5964/jnc.v4i2.110

Abstract

While the approximate number system (ANS) has been shown to represent relations between numerosities starting in infancy, little is known about whether parallel individuation – a system dedicated to representing objects in small collections – can also be used to represent numerical relations between collections. To test this, we asked preschoolers between the ages of 2 ½ and 4 ½ to compare two arrays of figures that either included exclusively small numerosities (< 4) or exclusively large numerosities (> 4). The ratios of the comparisons were the same in both small and large numerosity conditions. Experiment 1 used a between-subject design, with different groups of preschoolers comparing small and large numerosities, and found that small numerosities are easier to compare than large ones. Experiment 2 replicated this finding with a wider range of set sizes. Experiment 3 further replicated the small-large difference in a within-subject design. We also report tentative evidence that non- and 1-knowers perform better on comparing small numerosities than large numerosities. These results suggest that preschoolers can use parallel individuation to compare numerosities, possibly prior to the onset of number word learning, and thus support previous proposals that there are numerical operations defined over parallel individuation (e.g., Feigenson & Carey, 2003; https://doi.org/10.1111/1467-7687.00313).

Highlights

While the approximate number system (ANS) has been shown to represent relations between numerosities starting in infancy, little is known about whether parallel individuation – a system dedicated to representing objects in small collections – can be used to represent numerical relations between collections
Given that the number range effect was observed in children at the earliest stages of number word learning and that these children performed above chance on comparisons of small numerosities even when area and numerosity were not congruent, our results suggest that the development of the ability to use parallel individuation to compare numerosities does not depend on number word learning
We know that children based their choices on the numerosities of the collections because the evidence for this explanation was found on comparisons where size and numerosity were incongruent – i.e., where children could not base their decision on the total area or the total perimeter of the collections because these were equated, and where they could not base it on the individual object sizes because these were larger in the collection with the smaller numerosity