title: Infants prospectively control reaching based on the difficulty of future actions: To what extent can infants' multiple-step actions be explained by Fitts' law?
abstract: Prospective motor control, a key element of action planning, is the ability to adjust one's actions with respect to task demands and action goals in an anticipatory manner. The current study investigates whether 14-month-olds can prospectively control their reaching actions based on the difficulty of the subsequent action. We used a reach-to-place task, with difficulty of the placing action varied by goal size and goal distance. To target prospective motor control, we determined the kinematics of the prior reaching movements using a motion-tracking system. Peak velocity of the first movement unit of the reach served as indicator for prospective motor control. Both difficulty aspects (goal size and goal distance) affected prior reaching, suggesting that both these aspects of the subsequent action have an impact on the prior action. The smaller the goal size and the longer the distance to the goal, the slower infants were in the beginning of their reach toward the object. Additionally, we modeled movement times of both reaching and placing actions using a formulation of Fitts' law (as in heading). The model was significant for placement and reaching movement times. These findings suggest that 14-month-olds can plan their future actions and prospectively control their related movements with respect to future task difficulties. (PsycINFO Database Record
authors.affiliation: Uppsala Child & Baby Lab, Department of Psychology, Uppsala University.
authors.forename: Janna M
authors.identifier: 0000-0001-5497-4001
authors.initials: JM
authors.lastname: Gottwald
authors.affiliation: Department of Developmental Psychology and Socialization, University of Padova.
authors.forename: Aurora
authors.initials: A
authors.lastname: De Bortoli Vizioli
authors.affiliation: Uppsala Child & Baby Lab, Department of Psychology, Uppsala University.
authors.forename: Marcus
authors.initials: M
authors.lastname: Lindskog
authors.affiliation: Uppsala Child & Baby Lab, Department of Psychology, Uppsala University.
authors.forename: Pär
authors.initials: P
authors.lastname: Nyström
authors.affiliation: Uppsala Child & Baby Lab, Department of Psychology, Uppsala University.
authors.forename: Therese
authors.initials: T
authors.lastname: L Ekberg
authors.affiliation: Uppsala Child & Baby Lab, Department of Psychology, Uppsala University.
authors.forename: Claes
authors.initials: C
authors.lastname: von Hofsten
authors.affiliation: Uppsala Child & Baby Lab, Department of Psychology, Uppsala University.
authors.forename: Gustaf
authors.initials: G
authors.lastname: Gredebäck
mesh_terms: D001696:Biomechanical Phenomena; D002657:Child Development; D005260:Female; D006040:Goals; D006801:Humans; D007223:Infant; D008297:Male; D008954:Models, Biological; D009043:Motor Activity; D011897:Random Allocation; D013997:Time Factors; D014741:Video Recording