Two experiments are reported that focus on manipulating both the context and the spatial precision of a computer-pointing task. Single goal-directed actions are compared to dual-phase tasks, where participants are required to sequentially attain two goal locations. Results support the idea that for movements in series, movement planning, and online feedback, control can occur simultaneously. Additionally, for single-phase tasks and the final phase of dual-phase tasks, the termination requirement influences the temporal components of the movement. The effects of termination and movement context appear to hold regardless of the spatial precision of the task. This suggests that the effects of spatial precision and movement termination are independent, although both have an impact on the deceleration time for goal-directed movements.
Eric A. Roy, Linda E. Rohr, and Patricia L. Weir
Sara M. Scharoun, David A. Gonzalez, Eric A. Roy, and Pamela J. Bryden
Young adults plan actions in advance to minimize the cost of movement. This is exemplified by the end-state comfort (ESC) effect. A pattern of improvement in ESC in children is linked to the development of cognitive control processes, and decline in older adults is attributed to cognitive decline. This study used a cross-sectional design to examine how movement context (pantomime, demonstration with image/glass as a guide, actual grasping) influences between-hand differences in ESC planning. Children (5- to 12-year-olds), young adults, and two groups of older adults (aged 60–70, and aged 71 and older) were assessed. Findings provide evidence for adult-like patterns of ESC in 8-year-olds. Results are attributed to improvements in proprioceptive acuity and proficiency in generating and implementing internal representations of action. For older adults early in the aging process, sensitivity to ESC did not differ from young adults. However, with increasing age, differences reflect challenges in motor planning with increases in cognitive demand, similar to previous work. Findings have implications for understanding lifespan motor behavior.
Sara M. Scharoun, Pamela J. Bryden, Michael E. Cinelli, David A. Gonzalez, and Eric A. Roy
This study investigated whether 5- to 11-year-old children perceive affordances in the same way as adults (M age = 22.93, SD = 2.16) when presented with a task and four tools (nail in a block of wood and a hammer, rock, wrench, and comb; bucket of sand and a shovel, wooden block, rake, and tweezers; and a screw in a block of wood and a screwdriver, knife, dime, and crayon). Participants were asked to select the best tool and act on an object until all four assigned tools had been selected. No explicit instructions were provided because we were interested in how task perception would influence tool selection and action. Results support the notion that the capacity to perceive affordances increases with age. Furthermore, differences in the way in which 5-year-olds acted on the screw in a block of wood demonstrated that the ability to detect some affordances takes longer to refine. Findings help to further the understanding of the development of perception-action coupling.
Eric A. Roy, Liana Brown, Tammi Winchester, Paula Square, Craig Hall, and Sandra Black
Apraxia is an impairment in the ability to pantomime or imitate gestures usually caused by a stroke more frequently to the left than the right hemisphere. Due to the complex nature of apraxia, disruptions to a number of different cognitive and motor processes have been proposed to underly this disorder. In order to examine disruptions to these processes the participation of a special population of people who have suffered a stroke has been enlisted. The role of memory has been particularly well elucidated in studies of this special population, as patients with left hemisphere damage exhibit a particular deficit in performing gestures from memory. In this paper, through use of a model depicting the stages involved in gestural production, the processes that might be affected at each stage by left hemisphere damage are examined. The implications of the “cognitive neuropsychology” approach for incorporating special populations into research in the movement sciences are considered.