ABSTRACT
Attention is absolutely invaluable in everyday life. There is also an important distinction between focused and divided attention. Focused attention is studied by presenting individuals with two or more stimulus inputs at the same time and instructing them to respond to only one. Divided attention is also studied by presenting at least two stimulus inputs at the same time. The chapter considers four key issues. These include: what is focused visual attention like? what is selected in focused visual attention? what happens to unattended visual stimuli? and what are the major systems involved in visual attention? The chapter discusses what the study of visual disorders has taught people about visual attention. In everyday life, general scene knowledge is used to focus visual search on areas of the scene most likely to contain the target object. Multiple-resource theory and threaded cognition theory both assume that dual-task performance depends on several processing resources each of which has limited capacity.
