Abstract
Visual-motor integration is an essential skill in children’s development for acquiring new movements in dynamic environments. This requires visuomotor adaptation, in which motor commands are adjusted in response to visual feedback. Previous studies in adults suggest the contribution of two stages: an early, attentive processing stage for rapid error reduction and a later, implicit stabilization stage. However, it is unclear how these processes mature. In a child-friendly task, typically-developing children (age 6-11 years with healthy vision) moved a mouse cursor straight to a target location. During learning and relearning, visual feedback of cursor location was rotated 45°, requiring corrective movement. There were 10 baseline (no-rotation), 60 learning, 30 washout (no-rotation), and 30 relearning trials. Initial directional errors were calculated as the angular difference between lines drawn from the start to the point of peak velocity and to the target. Movement onset time and total movement time were also calculated. All measurements were compared to those of adults using the same paradigm. Younger (<8 years) and older (>8 years) children showed decreased errors across learning trials and between learning and relearning (p’s<0.05) blocks. The rate of error reduction increased with age, although children and adults reached the same level by the end of learning and relearning blocks. Errors decreased linearly across trials in younger children and exponentially in older children and adults. Onset time was slower in both groups of children than in adults. Movement time was similar across all groups during learning and relearning, and accelerated during washout in older children and adults. Younger children may achieve visuomotor adaptation in a qualitatively different manner from that of older children and adults. Early-stage processes appear to be immature before age 9, requiring reliance on slower, later-stage mechanisms. Older children use flexible, explicit movement strategies that are closer to those of adults.