Fig. 1.

Experimental shape-matching conditions. The shapes template was presented to the child just before beginning the task. (a) Easy: the easy condition had the same shape types, (b) moderate: the moderate condition had two different shape types, and (c) difficult: the difficult condition had multiple shape types that were different from each other. The children were asked to match the maximum number of shapes with the corresponding template for 30 s. The conditions were randomized and each task condition was repeated four times.