Visual Attention: The Active Vision Perspective

This chapter discusses the relationship between covert visual attention and overt movements of the eyes. One of the most frequently emphasised facts concerning visual attention is the ability to attend covertly to a location in the visual field without directing the eyes to that location. Based on this, the “mental spotlight” metaphor has been widely prevalent and has given rise to much experimental work. An important, but rather neglected, question concerns what role such a mental-spotlight process might play in vision. The compelling nature of the spotlight metaphor seems likely to arise because of its similarity with overt movements of the eyes. This leads to the suggestion that covert attention is involved in some form of mental scanning. We will argue that this account is not satisfactory. An alternative account, termed active vision, develops from the fact that overt eye scanning occurs several times each second in many tasks. Analysis of information intake during text reading, scene perception and visual search suggests that no additional covert scanning occurs in these cases. Evidence however suggests that attentional processes may operate to assist in pre-processing information in the visual periphery at the location to which the eyes are about to be directed. Covert attention to peripheral locations thus acts to supplement, not substitute for, actual movements of the eyes.