From objects to action: a neuropsychological analysis

This thesis is concerned with the factors that determine the performance of everyday action. Six empirical chapters are subsequently presented. First, I sought to investigate the effects of the presence of distractors and of task load on the performance of everyday life tasks, comparing a patient with ADS and controls operating with a task load (Chapter 2). The data indicate that controls and patients with ADS may suffer different demands. The role of the task schema on ADL was examined in Chapter 3. The results showed that there is a problem in using task schema to drive action under the on-line constraints of performing the action. Relation between object recognition and action was tested in Chapters 4 and 5. I showed that ‘object use’ effect was maintained even when the patients showed impaired semantic access for the objects. The final empirical study (Chapter 7), investigated the role of eye movements on performing an everyday. There were proportionately more unrelated fixations and more fixations concerned with locating objects in the ADS patient than in controls. In addition, eye movements away from objects being used were made earlier in the ADS patient, and toying errors were linked to multiple, brief fixations being made to the object involved. In the final chapter (8), I review the evidence from across the thesis and discuss the implications of the work for understanding both normal and disordered everyday actions. The results not only point to the complexity of processes supporting such actions, but also to the critical interactions between action and attention in such tasks