Preschool children adapt grasping movements to upcoming object manipulations: Evidence from a dial rotation task.

In adults, the motor plans for object-directed grasping movements reflects the anticipated requirements of intended future object manipulations. This prospective mode of planning has been termed second-order planning. Surprisingly, second-order planning is thought to be fully developed only by 10 years of age, when children master seemingly more complex motor skills. In this study, we tested the hypothesis that already 5- and 6-year-old children consistently use second-order planning but that this ability does not become apparent in tasks that are traditionally used to probe it. We asked 5- and 6-year-olds and adults to grasp and rotate a circular dial in a clockwise or counterclockwise direction. Although children's grasp selections were less consistent on an intra- and inter-individual level than adults' grasp selections, all children adjusted their grasps to the upcoming dial rotations. By contrast, in an also administered bar rotation task, only a subset of children adjusted their grasps to different bar rotations, thereby replicating previous results. The results indicate that 5- and 6-year-olds consistently use second-order planning in a dial rotation task, although this ability does not become apparent in bar rotation tasks.

Larger between-task crosstalk in children than in adults: Behavioral results from the backward crosstalk paradigm and a diffusion model analysis.

In dual-task settings, one can find influences from Task 2 processing even on Task 1 performance, an effect referred to as the backward crosstalk effect (BCE). The size of the BCE has been taken as an index of how well Task 1 processing can be shielded against concurrently ongoing Task 2 processes. In the current study, we compared the size of the BCE between adults and a group of 5- and 6-year-old children. First, the BCE turned out to be larger in children than in adults. Second, both groups exhibited a comparable adjustment of behavior in response to just experienced conflict; in both groups, the BCE was smaller following conflict trials than following no-conflict trials. Third, a diffusion model analysis suggests that the source for the BCE is different in adults than in children. In particular, not parallel Task 2 response activation appears to be the source of the BCE in children. Rather, non-decisional processes appear to be responsible for the BCE in this age group. Thus, this study shows that (a) 5- and 6-year-old children can perform dual-tasks, but (b) they show slightly larger signs of between-task crosstalk, and (c) the exact reasons for this appear to be different from those responsible in adults.