Wk10 Attention Flashcards
What are two key ideas about how attention works?
Capacity and selectivity
What attention is NOT?
Alertness and arousal
What is capacity of attention?
The amount of perceptual resources available for a task/process, which can vary with the task or individual.
What is selectivity of attention?
How perceptual resources are allocated to different subsets of info in a flexible way. What gets processed and doesn’t.
What does the cocktail party effect show?
Attention can be re-directed and info selected in various ways.
What is one of the most salient pieces of info in the dichotic listening task?
Your own name.
Where does early selection propose the attentional filter is?
After sensory registration, before perceptual/semantic analysis.
Where does late selection propose the filter is?
After perceptual/semantic analysis
Theory of selection proposes increased interference from irrelevant info? And why?
Late selection; more time spent processing irrelevant info for meaning.
how do distractors interfere with attention? 3
Slowed RT Reduced accuracy Changes to trajectories in moving to targets
What are the RT costs of irrelevant info?
It slows responses, particularly when opposite responses need to be inhibited
What changes to movement trajectories towards a target show about distractors?
The distractors is still processed and makes its way into movement calculation. Even when not a physical obstacle.
Is distractors interference due to obstruction in the physical world?
No, eye saccades are affected by (recoded) by Irrelevant information.
What are attention mechanisms we use when dealing with busy visual scenes? 6
Overt (eye movements) Shifting attention Top-down/Bottom-up Spotlight Zoom lens Parrallel/serial search
What is an overt deployment of attention?
Eyes move to shift attention
What is covert deployment of attention?
Eyes are fixed but attention shifts
Does the type of stimulus determine the extent of neuronal activation?
Yes
What are three components of shifting attention?
- Disengagement 2. Movement 3. Engagement
What three brain areas are involved in shifting attention?
Disengagment = right parietal lobe Movement = superior colliculus Engagement = thalamus
What is the poster cuing paradigm? How does it use valid and invalid trials?
An endogenous cue (arrow symbol) is used to cue attention. Trials can be valid or invalid where arrow is correctly signalling where the target will appear.
What are the results of the posner cuing paradigm?
Valid trials (correct arrow cues) provide RT benefit. Invalid trials incur cost; due to disengagement.
What happens when endogenous cues shift attention?
attention must voluntarily pushed from the central cue.
What happens when exogenous cues shift attention?
Attention is drawn to the location of cue and cannot be ignored.
Why do monkey studies suggest that V1 doesn’t process attended or non-attended stimuli?
No difference in V1 activation regardless of whether a covert point is attended or not.
What do monkey studies show about which areas of visual processing respond to covert vs overt attention?
V4/IT reacts to complex stimuli which are covertly attended.
What do ERPs show about covert attention in humans?
Valid cues result in enhanced P1 and N1 over right occipital cortex. This shows enhanced processing of validly cued target.
What three components of a ‘spotlight’ does attention share?
It has a fringe, a focus, and a margin. Clear in the middle, less clear further out.
How is attention like a zoom lens? What task illustrates this shift in attention?
It can narrow and expand (shown by local global tasks)
What is the relationship between interference from distractors and visual degrees?
Less than 1 deg = large interference
What is distributed attention?
“Pop out” parallel processing
What is focused attention?
Serial processing; selecting bits of the environment at a time
What is visual processing when using focused attention?
A series of attentional fixations, each covering a different region of the visual field.
What types of ERPs are found in distributed attention search?
Frontal and occipital activations for pop out feature search
What are the relationships between # of distractors and response time for parallel and serial search?
No RT cost for parallel search due to distractors. Whereas, distractors increase RT for serial search.
What does inattentional blindness tell us?
We cannot always process features which were not attended to; the filter
What are critical areas involved in left sided neglect and extinction?
Right parietal lobe: angular gyrus and parahippocampal gyrus; after middle cerebral artery stroke.
What tasks can be used to test hemispatial neglect?
Line bisection, copying, cancellation, drawing from memory.
What is impaired in left-sided neglect? 4
Disengagement from right sided stimuli Shifting & engagement to left sided stimuli Capacity limits (difficulty) Distributed attention
How do eye movements change after the onset of spatial neglect?
Patients cant look to left side, but this is somewhat resolved after a process of weeks
How do you show unconscious processing in spatial neglect patients? What does this show about the mental processes affected?
Pictures of a house, one is on fire. Ps cant tell which one is different, but they respond to “which house would you prefer to live in” correctly. There is some unconscious representation of left sided objects.
What shows that mental representation is affected by spatial neglect, not physical representation?
Piazza del Duomo study; spatial neglect remains for imaginary shifts in space (mental representation)
How is visual extinction different from neglect?
Better detection of left events when nothing is on the right, or presented earlier than right.
Why do we not get right sided neglect? What would happen to a lesion on either the left or right side?
The right hemisphere covers some of the right visual fields as well as left vf. Left lesion = little effect (right hemi processes some of both VFs) Right lesion = loss of left side
