Attention & Spatial Processing Flashcards
Attention
Attention is the process through which certain information is selected for further processing while other information is discarded. Selective attention is beneficial in increasing efficiency and avoiding sensory overload
Inattention blindness
The failure to be aware of certain stimuli because attention is focused on something else
Change blindness
failing to notice the appearance or disappearance of objects between 2 scenes
endogenous orienting
attention is guided by the goals of the perceiver
Top-down processing
Exogenous oriented
Attention is guided by environmental stimuli
Bottom-up processing
Shifting attention between 2 superimposed images in same space (brain areas)
Face: Fusiform face area
House: Parahippocampal place area
Attentional blink
Inability to report a stimulus if it appears right after another target stimulus
The parietal lobes (4)
- Specialized for spatial processing - “where” route
- Bring together different types of spatial representation required for action - “how” route
- Respond to behavioural saliency (abrupt onset)
- Integrate visual spatial info with postural info (locating objects in space)
- Regions in the parietal cortex combine:
- visual
- somatosensory
- auditory
- postural …….signals
LIP
Lateral Intra-Parietal Area
- Contains neurons that respond to salient stimuli in the environment and are used to plan eye movements
- Multi-sensory part of the brain
- Imp or attention: responds to stimuli that are unexpected
- Codes a spatial salience map (left & right hemispheres have diff biases)
- Enables convert & overt orienting
Salience map
A spatial layout that emphasizes the most behaviourally relevant stimuli in the environment
Covert orienting
Movement of attention from one location to another without moving eyes/ body
Overt orienting
Movement of attention from one location to another combined with movement of eyes/body
- Saccades: fast ballistic movement of eyes
Frontal parietal attention mechanisms
- Orienting cues
(arrows) - activate LIP and the frontal eye field (FEF)
- no overt response required
FEF
Frontal eye field
- part of the frontal lobes responsible for the voluntary movement of the eyes
Pseudo-neglect
A tendency to attend to the left side of space
This is due to hemispheric differences in spatial and non-spatial attention. The right parietal lobe contains richer representation of space, this includes all the left space and some right of the right space. The left parietal lobe however gives a more impoverished representation of space and attends to predominantly to the right side
TMS studies have shown that the right parietal lobe is important for attending to salient stimuli while the left parietal lobe is implicated in suppresing non-salient stimuli
Therefore patients with damage to the right parietal lobe have more impairments in spatial attention than those with left parietal damage. This particularly effects the right side of space
Feature Integration Theory
States that attention selects perceptual objects and combines different features of those objects into a reportable experience.
- These features are encoded in parallel and prior to attention
- Therefore if and object does not share features with another object it appears to pop-out and is therefore detected without the need for selective attention
- If an object shares features with objects than it requires attending and searching in a serial manner.
Negative Priming
when an ignored object becomes an attended object on the subsequent trial, then participants are slower at processing it (there is cost of processing)
Early & Late selection
○ Selection depends on the demands of the task
○ In early selection, the stimulus does not need to be completely perceptually analysed & encoded before it is selected for further processing or discarded.
§ Information is therefore selected according to perceptual attributes
§ Early selection is based on perceptual features
○ In late selection: attended and ignored inputs are processed up to the level of meaning (semantics) before being selected for further processing
Late selection is based on meaning
