Attention: Effect on Perception

Attention is the mechanism that allows us to select relevant information for processing from the vast amount of stimuli we are confronted with, prioritizing some while ignoring others. Attention can affect perception by altering performance—how well we perform on a given task—or by altering appearance— our subjective experience of a stimulus or object. Visual attention is commonly divided into three types: (1) spatial attention, which can be overt, when an observer moves his or her eyes to a relevant location and the focus of attention coincides with the movement of the eyes, or covert, when attention is deployed to relevant locations without accompanying eye movements; (2) feature-based attention, which is deployed to specific features (e.g., color, orientation or motion direction) of objects in the environment, regardless of their location; (3) object-based attention (which will not be discussed further here). By focusing on different kinds of information, these types of attention optimize our visual system's performance: whereas spatial attention guides an observer to a particular location, feature-based attention guides an observer to a particular feature of the object or stimulus. For instance, when waiting to meet a friend at a café, we may deploy spatial attention to the door (where he or she is likely to appear) and feature-based attention to orange objects (because he or she often wears an orange jacket).