Differential accuracy of aimed movements to visual and somatic targets in young children

Children, aged 2.5-8 years, were required to touch accurately a target located either on their bodies or on the chair in which they sat. Movements were made when visual information was: 1. complete (target lit for 3 s, room illuminated); 2. partial (target lit for 3 s, room dark); 3. reduced (target lit for 0.7 s, room dark); and finally, when the target was somatically specified. Movements to visible targets did not differ in any important way as a function of target location with respect to on/off body. Accuracy improved with age to visually but noto somatically specified targets, decreased with decreasing availability of visual information, and was poorest to somatically specified targets. We conclude that during development, the sense-modality through which the target is specified and the visibility of the arm/hand during the movement, but not the personal/extra personal visible space in which the target is located, are important determinants of reaching performance.