What visual information do children and adults consider while switching between tasks? Eye-tracking investigation of cognitive flexibility development.

This study investigated the visual information that children and adults consider while switching or maintaining object-matching rules. Eye movements of 5- and 6-year-old children and adults were collected with two versions of the Advanced Dimensional Change Card Sort, which requires switching between shape- and color-matching rules. In addition to a traditional integrated version with bidimensional objects (e.g., a blue bear), participants were tested on a dissociated version with pairs of unidimensional objects as stimuli (e.g., a noncolored bear beside a blue patch) so that fixations on the relevant and irrelevant dimensions of the stimuli could be distinguished. The fixation times were differentially distributed depending on whether children had to switch or maintain matching rules. Trial type differences in fixation times were primarily observed for the cues and the relevant and irrelevant dimensions of the stimuli, whereas responses options were seldom fixated even by the youngest children. In addition, the shape modality of the stimulus was more fixated than the color modality whether or not shape was relevant. Finally, the fixation patterns were modulated by age. These results suggest that switch costs are more related to selection of the relevant dimension on the stimulus than to response selection and point to age-related differences in strategies underlying flexible behavior.