The recognition of everyday objects changes grasp scaling

Current concepts of action and perception emphasise a dissociation between conscious visual recognition and visual action control. These models do not expect an effect of the recognisable identity of an object on the kinematic parameterisation of grasping movements under binocular viewing conditions without pre-test learning periods. We performed two experiments presenting participants with familiar everyday objects or neutral geometrical objects. The participants grasped either with full vision or without visual feedback after movement onset without an explicit training phase before the experiment. In general, the familiarity of objects increased the sensitivity to physical object size changes measured by the slope of the maximal grip aperture relative to object size. We conclude that associations between object identity and a particular size, presumably encoded in long-term memory, are integrated in the parameterisation of grasping movements upon the identification of individual objects.

► The familiarity of objects increased the sensitivity to physical object size changes.
► Object characteristics encoded in memory are integrated in the implementation of the grasp.
► Memorised identity-size associations represent one size-depth cue among others for visual action control.
► Experiments using artificial objects presumably underestimate the effect of recognition on action implementation.