A failure to notice—or at least to report—a stimulus that would be easily reportable if it were attended.
Information in our understanding of scenes that helps us find specific objects in scenes (e.g., objects do not float in air, faucets are near sinks).
An effect of attention on the response of a neuron in which the neuron responding to an attended stimulus gives a bigger response.
As a neurological symptom, (1) in visual attention the inability to attend to or respond to stimuli in the contralesional visual field (typically, the left field after right parietal damage); (2) ignoring half of the body or half of an object.
serial self-terminating search
A search from item to item, ending when a target is found.
The number of items in a visual display.
The processing of a stimulus that occurs before selective attention is deployed to that stimulus.
Search for a target defined by the presence of two or more attributes (e.g., a red, vertical target among red horizontal and blue vertical distractors).
The goal of a visual search.
The tendency not to perceive or respond to the second of two different target stimuli amid a rapid stream of distracting stimuli if the observer has responded to the first target stimulus within 200–500 milliseconds before the second stimulus is presented.
Search in which attention can be restricted to a subset of possible items on the basis of information about the target item’s basic features (e.g., its color).
An effect of attention on the response of a neuron in which the neuron responding to an attended stimulus responds more precisely. For example, a neuron that responds to lines with orientations from –20 degrees to +20 degrees might come to respond to ±10-degree lines.
An inability to perceive more than one object at a time. Simultagnosia is a consequence of bilateral damage to the parietal lobes (Balint syndrome).
A loose collection of unbound features (size, color, and so forth) that will be a recognizable object, once attended.
reaction time (RT)
A measure of the time from the onset of a stimulus to a response.
The form of attention involved when processing is restricted to a subset of the possible stimuli.
In visual search, any stimulus other than the target.
In each cerebral hemisphere, a lobe that lies toward the top of the brain between the frontal and occipital lobes.
The average of and distribution of properties like orientation or color over a set of objects or over a region in a scene.
In visual attention, the inability to perceive a stimulus to one side of the point of fixation (e.g., to the right) in the presence of another stimulus, typically in a comparable position in the other visual field (e.g., on the left side).
parahippocampal place area (PPA)
A region of extrastriate visual cortex in humans that is specifically and reliably activated more by images of places than by other stimuli.
The vividness of a stimulus relative to its neighbors.
fusiform face area (FFA)
A region of extrastriate visual cortex in humans that is specifically and reliably activated by human faces.
The visual field on the same side as a brain lesion.
An erroneous combination of two features in a visual scene—for example, seeing a red X when the display contains red letters and Xs but no red Xs.
The challenge of tying different attributes of visual stimuli (e.g., color, orientation, motion), which are handled by different brain circuits, to the appropriate object so that we perceive a unified object (e.g., red, vertical, moving right).
stimulus onset asynchrony (SOA)
The time between the onset of one stimulus and the onset of another.
A stimulus that might indicate where (or what) a subsequent stimulus will be. Cues can be valid (giving correct information), invalid (incorrect), or neutral (uninformative).
The description of the structure of a scene (e.g., enclosed, open, rough, smooth) without reference to the identity of specific objects in the scene.
A portion of the visual field with no vision or with abnormal vision, typically resulting from damage to the visual nervous system.
Search for a target in a display containing distracting elements.
The failure to notice a change between two scenes. If the gist, or meaning, of the scene is not altered, quite large changes can pass unnoticed.
A search in which multiple stimuli are processed at the same time.
Search for a target defined by a single attribute, such as a salient color or orientation.
feature integration theory
Anne Treisman’s theory of visual attention, which holds that a limited set of basic features can be processed in parallel preattentively, but that other properties, including the correct binding of features to objects, require attention.
A failure to detect the second occurrence of an identical letter, word, or picture in a rapidly presented stream of stimuli when the second occurrence falls within 200–500 milliseconds of the first.
The visual field on the side opposite a brain lesion. For example, points to the left of fixation are contralesional to damage in the right hemisphere of the brain.
rapid serial visual presentation (RSVP)
An experimental procedure in which stimuli appear in a stream at one location (typically the point of fixation) at a rapid rate (typically about eight per second).
Any of the very large set of selective processes in the brain. To deal with the impossibility of handling all inputs at once, the nervous system has evolved mechanisms that are able to restrict processing to a subset of things, places, ideas, or moments in time.