Abstract
Previous studies have shown that grasped objects are rapidly assimilated into the representation of the body. Object assimilation requires the brain to acquire structural properties of the object, which can be acquired through multiple sensory modalities (e.g. haptic exploration). The present study investigated the role of vision in acquiring an object's structure. Our experiments investigated whether visual features that are “perceived” as a whole object would be assimilated as single structural unit. The experiment was a 2 × 2 design using whole objects or discontinuous object parts, which were either displayed in full view of the observer or partially occluded. Importantly, when participants viewed the discontinuous object parts behind the occluder they appeared to be whole object. We used a paradigm, which employs positive afterimages, as a means to assess the degree to which objects are assumed into the body representation. When the objects were in full view of the observer, we found robust assimilation of the whole object, whereas the discontinuous object part was not assimilated. In the occluded condition, there was weaker assimilation for the whole object relative to when it was observed in full. The critical condition that emerged was that of the occluded discontinuous object parts, which were perceived as a whole. In this condition we found the discontinuous part of the object was assimilated, albeit more weakly than when the whole object was occluded. The results suggest that visual features interpreted as a whole object by the visual system, are more readily integrated as single structural unit into the body representation.