Helping children apply their knowledge to their behavior on a dimension-switching task

To investigate why 3-year-olds have difficulty in switching sorting dimensions, children of 3 and 4 years were tested in one of four conditions on Zelazo's card sort task: standard, sleeve, label and face-up. In the standard condition, children were required to sort blue-truck and red-star cards under either a blue-star or red-truck model card, first by color or shape, and then by the other dimension. Here 3-year-olds sorted correctly until the dimension changed, they continue to sort by the initial dimension. The sleeve condition (placing the sorting cards in an envelope prior to sorting) had little effect. In the label condition, the child labeled the relevant sorting dimension on each trial. Most 3-year-olds succeeded, evidently their labeling helped them refocus their attention, overcoming 'attentional inertia' (the pull to continue attending to the previously relevant dimension). In the face-up condition, attentional inertia was strengthened because sorted cards were left face-up; 4-year-olds performed worse than in the standard condition. We posit that attentional inertia is the core problem for preschoolers on the card sort task.