%A Jeroen B.J Smeets %A Eli Brenner %J Studies in ecological psycholgy: Proceedings of the Fourth European Workshop on Ecological Psychology %T Multiple specification of an object's size for picking it up. %X Subjects were asked to pick up disks. The apparent size of the disks was manipulated by a visual illusion. Of the two aspects of the action which depend on the objects size, only one was affected by the illusion. We conclude that different aspects of an action are controlled independently, instead of being co-ordinated on the basis of one perceptual variable. %K human arm hand movements grasping lifting size weight illusion fingers force acceleration %P 147-149 %E A.M.L. Kappers %E C.J. Overbeeke %E G.J.F. Smets %E Stappers P.J. %D 1996 %I Delftse Universitaire Pers, Delft %L cogprints853