The effect of stimulus variability on children's judgements of quantity

Abstract

This study investigates the effect of stimulus variability on development of the ability to make quantity judgements related to area. Participants were 241 children (aged 4, 5, 6, 8, and 12 years) and 82 university students, who were asked to compare the quantities in 2 sets of 5 chocolate bars of constant width but variable length. Participants indicated which set contained more chocolate or that the amounts of chocolate were equal. Judgement accuracy of 12-year-olds and adults decreased monotonically as the variance of bar lengths increased. In younger children, performance was low when variance was very low or very high, but accuracy was higher for intermediate levels of variance, thus resulting in an inverted U-shaped effect. This pattern was confirmed in a second experiment in which we controlled for a possible age-related response bias against “equal” judgements. Findings suggest that judgements of quantity are based on a mixture of learned heuristics and comparisons of approximate quantity representations, both of which develop throughout childhood.

Keywords:

• Quantity judgements
• Area
• Stimulus variability
• Cognitive development

View correction statement:

Erratum

This article was originally published with errors. This version has been corrected. Please see erratum/corrigendum (http://dx.doi.org/10.1080/02687038.2013.813765).

Notes

¹ Each test was performed according to the principle of marginality (Type II tests), i.e., testing each term after all others, except ignoring the term's higher order relatives (for details see Fox, 1997).