Abstract and Keywords
As discussed in Chapter 11 of this volume, attention plays a role in the perception of simple stimuli, serving as a gain control that enhances the speed or accuracy of feedforward visual processing. However, additional attentional mechanisms are needed to support the iterative, reentrant processes and perception-action loops that are involved in the perception of complex, multiple-element stimulus arrays, and the event-related potential (ERP) correlates of these additional attentional mechanisms will be the focus of the present chapter. The first half of the chapter begins by discussing the computational problems that must be solved by these mechanisms and the sequence of steps involved in processing complex stimulus arrays, which include storing a target template in working memory, detecting relevant features, focusing attention on a peripheral location, shifting overt attention to the attended location, and then expanding or contracting attention around the object at this location. The ERP components corresponding to each of these steps are then described. The second half of the chapter provides a closer look at N2pc and related contralateral components that reflect the focusing of attention onto a peripheral location.