Abstract
This study explored the use of advance information in the control of reach-to-grasp movements. The paradigm required participants to reach and grasp illuminated blocks with their right hand. Four target blocks were positioned on a table surface, two each side of the mid-saggital plane. In the complete precue condition, advance information precisely specified target location. In the partial precue condition, advance information indicated target location relative to the midsaggital plane (left or right). In the null condition, the advance information was entirely ambiguous. Participants produced fastest responses in the complete precue condition, intermediate response times in the partial condition, and the slowest responses in the null condition. This result was observed in adults and four groups of children including a group aged 4–6 years. In contrast, children with Developmental Coordination Disorder (DCD, n = 11, aged 7–13 years) showed no advantage of partial precueing. Movement duration was determined by target location but was unaffected by precue condition. Movement duration was a clear function of age apart from children in the DCD group who showed equivalent movement times to those of the youngest children. These findings provide important insights into the control of reach-to-grasp movements and highlight that partial cues are exploited by children as young as 4 years but are not used in situations of abnormal development.
Acknowledgments
Preparation of this manuscript was supported in part by a grant to the authors from the National Health and Medical Research Council, Australia.
Notes
Note: The initials identify the child. Age refers to chronological age (in years) at the time of testing. The total Movement ABC (MABC) score is given together with scores on three different sections (manual dexterity, ball skill, and balance). PPVT refers to scores from Peabody Picture Vocabulary Test.