Week 4: Attention Flashcards
What are the options for processing rich stimuli?
- full parallel processing
- Selection for processing
- Selection for action
What is Vigilance ?
Ability to uphold critical task performance across long time periods (concentration)
What is arousal?
Global physiological and psychological state of the organism (from deep sleep to hyper-alertness)
What is attention?
- a selection mechanism
- An amplification and inhibition mechanism
In what sense is attention a selection mechanism?
- selects one or more stimuli for in-depth processing
- Selection happens in light of competition
- Limited metabolic resources → need for efficient representational codes relying on a sparse collection of active neurons
- Attention as a spotlight
In what sense is attention an amplification and inhibition mechanism?
feedback from top-down areas and recurrent processing amplify information in early areas
What is selective attention?
- selection of one or more alternative stimuli for in-depth cognitive processing
- Typically necessary due to limitations and bottlenecks in cognitive resources → not all sensory stimuli can undergo deep processing
Why are fixation points important for attention?
under most natural conditions, point of gaze fixation coincides with focus of attention
→ Fixation patterns as good indicator of a persons current attention
Why can we not process the entire visual field in parallel?
One reason is the low density of cones in the periphery
What is covert attention?
- ability to select a region of visual space for in-depth processing without moving the eye
- Requires a voluntary decoupling of attentional focus and gaze
What are different types of attention?
- spatial attention: attention to particular location
- Feature-based attention: specifics aspects of objects, regardless of location
- Object-based attention: guided by object structure
Why are eye movements important for spatial attention?
- eye movements and visual selective attention are controlled by highly similar networks in parietal (IPS) and frontal cortex (FEF)
- Could reflect voluntary and „artificial“ suppression of eye moments in covert attention tasks
What are the two attentional networks?
- Dorsal and ventral
- Are antagonistic
What is the dorsal attentional network?
- includes IPs/SPL and FEF
- Generated by endogenous cues (self-generated)
- Top-down orientation of attention
- Voluntary
What is the ventral attentional network?
- includes TPJ and VFC
- Generated by Exogenous cues (coming from environment)
- Bottom-up capture of attention
- Involuntary
- Dependent on the saliencey of cues
What is salience?
= conspicuous, noticeable, important
A feature of a stimulus, not the observer
What are findings of Posner cueing task ?
- Attention shift to target area occurs prior to eye movement
- Three mental operations during covert orienting: disengagement of current focus, movement to selected target, engagement of selected target
- Parietal lobe damage affects ability to orient and detect targets from invalid trials
- Children with ADHD have slower reaction times
What happens to unattended stimuli?
- dichotic listening experiments:
- Two simultaneous messages, one to each ear
- Task: shadowing (repeating) of one channel
- Performance is poor when voices are similar
- Unable to report contents of ignored ear
→ indicates early selection/ filtering
What does early selection mean?
stimulus can be selected for further processing before perceptual analysis of the stimulus is complete
What does late selection mean?
Perceptual system first processes all inputs equally and then selection takes place at higher stages of information processing
What is Broadbent‘s filter model?
- model that indicated early selection, prior to semantic analysis
- All stimuli arrive at selective filter
- Only selected stimuli are forewarded to Limited Capacity System (limited capacity decision channel, LTM storage) and responses
- Filter is supposed to protect LC-system from overload
What speaks for a late selection?
- intrusions of salient, unattended inputs
- One can remember more details about unattended channels if personal details are included
- Persistence of semantic when ear is switched
What speaks for early selection?
Dichotic listening experiments
Why is the question of late or early selection relevant ?
- Selection seems to be one of the core features of visual processing
- We want to know when we become conscious of stimulus
- We know that memory is limited, but not whether perception is limited or if it overflows cognitive access
What is parallel vs serial visual search?
Parallel search: singleton, pop-out, preattentive, RT constant, bottom-up attention
Serial search: feature conjunction, attention required, RT increases with set size, top-down attention, need to integrate several features in order to perform task
What is Treisman‘s feature-integration theory?
- different cortical maps for different features
- Features are processed in parallel
- Feature conjunction requires attention to bind different features across different maps
What is Neglect?
- damage to the right hemisphere of he brain causes inability to attend to the contralateral visual Field
- Affects memory and mental representations
