ACCURACY DEMANDS IN NATURAL PREHENSION

In a recent kinematic analysis of prehensile movements directed toward cylindrical objects of different diameter, Marteniuk, Leavitt, MacKen zie and Athenes (1990) reported a negative linear relationship between object diameter and movement time. The present study was set up to in vestigate whether this effect was due to the manipulation of (i) objec t size, or (ii) surface area available for contact. The findings of Ma rteniuk et al. were not be replicated, as no effect on movement time w as found for the range of object diameters studied (3-7 cm). However, a significant difference in movement time was found to exist between d ifferently shaped objects, suggesting that the area available for cont act is an important determinant of movement duration.