Visual Attention

Visual attention is a form of visual attention that involves directing attention to a location in space.

Visual attention allows humans to selectively process visual information through prioritization of an area within the visual field. A region of space within the visual field is selected for Visual attention and the information within this region then receives further processing. Visual attention Research shows that when spatial attention is evoked, an observer is typically faster and more accurate at detecting a target that appears in an expected location compared to an unexpected location.

Visual attention is distinctive from other forms of visual attention such as object-based attention and feature-based attention. These other forms of visual attention select an entire object or a specific feature of an object regardless of its location, whereas Visual attention selects a specific region of space and the objects and features within that region are processed.

A key property of visual attention is that attention can be selected based on spatial location and spatial cueing experiments have been used to assess this type of selection. In Posner’s cueing paradigm, of Visual attention, the task was to detect a target that could be presented in one of two locations and respond as quickly as possible. At the start of each Visual attention trial, a cue is presented that either indicates the location of the target (valid cue) or indicates the incorrect location thus misdirecting the observer (invalid cue). In addition, on some Visual attention trials there is no information given about the location of the target, as no cue is presented (neutral trials). Two distinct cues were used; the cue was either a peripheral ‘flicker’ around the target’s location (peripheral cue) or the cue was centrally displayed as a symbol, such as an arrow pointing to the location of the target (central cue).

Visual attention cueing tasks typically assess covert Visual attention , which refers to attention that can change spatially without any accompanying eye movements. To investigate Visual attention , it is necessary to ensure that observer’s eyes remain fixated at one location throughout the task. In Visual attention tasks, subjects are instructed to fixate on a central fixation point. Typically it takes 200 ms to make a saccadic eye movement to a location. Therefore, the combined duration of the cue and target is typically presented in less than 200 ms. This ensures that covert Visual attention is being measured and the effects are not due to overt eye movements. Some Visual attention studies specifically monitor eye movements to ensure that the observer’s eyes are continually fixated on the central fixation point.