40 terms

Chapter 7 - Attention

Sensation & Perception
Any of the very large set of selective processes in the brain
Selective attention
The form of attention involved when processing is restricted to a subset of the possible stimuli
External attention
Attending to stimuli in the world
Internal attention
Attending to one line of thought over another or selecting one response over another
Overt attention
Directing a sense organ toward a stimulus, like pointing your eyes or turning your head
Covert attention
Attending without giving an outward sign you are doing so
Divided attention
Splitting attention between two different stimuli
Sustained attention
Continuously monitoring some stimulus
Reaction time (RT)
A measure of the time from the onset of a stimulus to a response
A stimulus that might indicate where (or what) a subsequent stimulus will be. Cues can be valid (correct info), invalid (incorrect info), or neutral (uninformative)
Stimulus onset asynchrony (SOA)
The time between the onset of one stimulus and the onset of another
Spotlight model
Attention is restricted in space and moves from one point to the next. Areas within the spotlight receive extra processing
Zoom lens model
The attended region can grow or shrink depending on the size of the area to be processed
Visual search
Looking for a target in a display containing distracting elements
The goal of a visual search
In visual search, any stimulus other than the target
Set size
The number of items in a visual search display
The efficiency of visual search
the average increase in RT for each item added to the display; measured in terms of search slope, or ms/item
Feature search
Search for a target defined by a single attribute, such as a salient color or orientation; efficient
The vividness of a stimulus relative to its neighbors
Parallel processing
Processing of multiple stimuli at the same time
Guided search
Search in which attention can be restricted to a substet of possible items on the basis of information about the target item's basic features (eg, its color)
Conjunction search
Search for a target defined by the presence of two or more attributes
- no single feature defines the target
- defined by the co-occurence of two or more features
- inefficient
- Serial Processing: items are processed one at a time
The larger the search slope (more ms/item), the less efficient the search
Efficient searches - have small slopes
Inefficient searches - have large slopes
Scene-based guidance
Information in our understanding of scenes that helps us find specific objects in scenes
The binding problem
The challenge of tying different attributes of visual stimuli, which are handled by different brain circuits, to the appropriate object so we perceive a unified object
- example: a vertical red bar moving to the right
--color, motion, and orientation are represented by separate neurons
Feature integration theory (aka Treisman's theory of visual attention)
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. (Basically, you can be "pre"attentive and look for something that is small and brown if you're looking for a mouse, and completely disregard the large, orange things in a visual search, but that you have to put those features together in your head first)
Preattentive stage
The processing of a stimulus that occurs before selective attention is deployed to that stimulus
Illusory conjunction
A false combination of two features in a visual scene; some features are represented independently and must be correctly bound together with attention
Rapid serial visual presentation (RSVP)
Used to study the temporal dynamics of visual attention.
An experimental procedure in which stimuli appear in a stream at one location (typically the point of fixation) at a rapid rate (typically about 8/sec)
Attentional blink
The difficulty in perceiving and responding to the second of two target stimuli amid a RSVP stream of distracting stimuli
The target is often missed if it appears within 200-500
Repetition blindness
A failure to detect the second occurrence of a letter, word, or picture in a RSVP stream of stimuli
The second occurrence is often missed when it appears within 200-500 ms of the first occurrence
3 ways responses of a cell could be changed by attention
1. Response enhancement
2. Sharper tuning
3. Altered tuning
Response enhancement
An effect of attention on the response of a neuron in which the neuron responding to an attended stimulus gives a bigger response (Suppose a cell responded to a range of different orientations but was maximally responsive to vertical lines. Attention might make the cell more responsive across the board; has been seen in the visual cortex)
Sharper tuning
An effect of attention on the response of a neuron in which the neuron responding to an attended stimulus responds more precisely. (Attention could make it easier for the neuron to find a weak vertical signal amid the noise of other orientations)
Fusiform face area (FFA)
An area in the fusiform gyrus of human extrastriate cortex that responds preferentially to faces according to fMRI studies
Parahippocampal place area (PPA)
A region of cortex in the temporal love of humans that appears to respond strongly to images of places (as opposed to isolated objects)
In visual attention, the inability to attend or respond to stimuli in the contralesional visual field. Typically, neglect of the left visual field after damage to the right parietal lobe
Contralesional field
The visual field on the opposite side of a brain lesion. For example, points to the left of fixation are contralesional to damage to the right hemisphere of the brain
Ipsilesional field
The visual field on the same side as a brain lesion.