Individual differences in disengagement of fixation and temperament: longitudinal research on toddlers.

It has been suggested that a shift occurs in the brain's control system from the orienting network in infancy to the executive network by the age of 3-4 years; however, there has been little empirical evidence of this shift during toddlerhood. Therefore, the present study examined how the orienting system in infancy is related to an effortful control system at a later age. Children were assessed longitudinally at 12, 18, 24, and 36 months of age, using a gap-overlap task in which dynamic geometrical-shape stimuli were presented. Parents completed temperament questionnaires about the children at each age. A delayed-gratification task was also given to 36-month-olds. Overall, saccadic latencies in the gap-overlap task were significantly faster at 36 months. At all ages, responses were slower during overlap trials than during gap or no-overlap trials. Longer latencies in the overlap condition were associated with low temperamental orienting/regulation scores at 12 months but with high effortful control scores at 18 and 24 months. The associations at 18 and 24 months are thought to represent a genuine positive association between effortful control and sustained and focused attention.