Analysing the adaptiveness of strategy choices using the choice/no-choice method: The case of numerosity judgement

Abstract

The present study tested the usefulness of the choice/no-choice method (Siegler & Lemaire, 1997) in the domain of numerosity judgement. Young adults were asked to judge all possible numerosities of blocks that were presented in a 7 2 7 grid. In the choice condition, subjects were allowed to choose freely between two strategies: (1) the addition strategy by means of which the number of blocks in different subgroups are added or (2) the subtraction strategy in which the number of empty squares in the grid is subtracted from the total number of squares in the grid. In two no-choice conditions, subjects were successively required to judge all numerosities of blocks by using solely one of both aforementioned strategies on all trials. The exclusion of selection effects in the no-choice conditions yielded unbiased estimates of strategy performance, which enabled investigating participants' strategy adaptiveness in the choice condition. Different measures of adaptiveness indicated that participants were very adaptive in their strategy choices. In addition, a new measure of individual strategy adaptiveness was developed. The results of this study are discussed in terms of Lemaire and Siegler's (1995) theoretical framework regarding strategic competence.