Dissociation between Verbal and Pointing Responding in Perspective Change Problems

Predicting the outcome of spatial transformations, such as viewpoint changes, is very important in everyday life. It has been shown that it is very difficult to point to where an object would be as if one is facing a different direction (perspective change problem). These difficulties are often attributed to the imagination process that is mentally rotating oneself or the object array. This chapter investigates this hypothesis by varying the 'imagination time' before the target is given. It presents two experiments showing that when using a pointing task, there is no improvement in performance even when the participants are allowed to complete the 'imagination' process first. In contrast, when using a verbal reporting task, participants are able to describe the egocentric angles of the imagined target location as quickly as the no-imagination control condition. These results suggest that participants are able to transform and maintain a representation of the new perspective, but this representation is accessible to a verbal system that subserves the verbal response task, but not to an action system that subserves the pointing task. Thus, functional features defined with respect to one cognitive system may not generalize to another cognitive system.