Nys, J. & Content, A.
Laboratoire Cognition Langage Développement (LCLD), Université Libre de Bruxelles (ULB), Brussels, Belgium
A Stroop-like paradigm was used with 57 adult participants who were asked to perform (1) a number judgment and (2) an area judgment on dot collections orthogonally varying along a discrete dimension (number of dots) and a continuous dimension (cumulative dot area). In the number comparison task, as expected, incongruent trials for which the largest number of dots corresponded to the smallest cumulative area led to larger error rate and reaction times than congruent trials for which number and area covaried positively. This finding suggests that area is automatically processed and integrated during a discrete quantity judgment task. Interestingly, a similar interference effect was observed in the area comparison task, providing evidence that adults are unable to ignore numerical features of the stimuli even when task-irrelevant. Moreover, participants tended to select the numerically largest collection when cumulative area, the task-relevant dimension, was equal for both sets. By contrast, in the number comparison task, they showed no preference for the set with the largest area when the number of dots was identical for both collections. Contrasting with earlier statements, these results support the view that, in adults, number is automatically extracted and acts as a more salient cue than area.