EXPRESS: Developmental grasp selection under flexible task constraints

Previous studies have reported no or reduced anticipatory grasp selection in younger children (3-4 years) for tasks with specific instructions, such as which hand to use. A possible reason could that planning becomes too difficult under such constraints. The present study therefore examined grasp selection when specific instructions were lifted. Children between 3 to 10 years of age were asked to move a plunger between shelves of a bookcase, and were free to use either hand, swap hands during transport and adopt any body posture. Younger children (3-6 years) more often used this extra flexibility by swapping hands and changing hand position. Children across all ages adjusted their initial grasp to the target shelf height, suggestive of anticipatory grasp selection. The effect of the target shelf on the initial grasp was smaller than in previous studies, possibly because children used the opportunity to adjust their grip during transport. The findings suggest that task constraints may have been a factor in why young children did not engage in anticipatory grasp planning in previous settings. Younger children may be able to plan ahead if the task does not get too complicated.