LECTURE 4 - Attention Flashcards
not including section 5 at the end of lecture 4
what is attention?
- cognitive mechanisms that help us select, modulate, and sustain focus on information that might be most relevant for behaviour
- ability to process information is capacity-limited
- attention functions as a spotlight, helping us to select and prioritize some info over others
what is external attention?
where we attend outwardly to select and modulate sensory information
what is internal attention?
- where we select, modulate, and maintain internally generated information
- such as thoughts, feelings, ways to respond, contents of memory
how are external and internal attention connected through working memory?
- researchers believe that the control over external attention is linked to working memory capacity
- working memory - our ability to keep selected information consciously in mind (internal attention)
what research study highlighted the link between external attention and internal attention (working memory)?
participants ranked high or low on working memory and assigned to one of three conditions
1. two red objects (targets) and two blue objects (distractors)
2. two red objects alone
3. four red objects alone
- hypothesized that participants with higher working memory should be able to more easily direct attention externally
- task with distractors should be just as easy or hard for them as the task without distractors
what were the results from the study on the link between external attention and internal attention (working memory)?
used event related potentials to show how hard the task is
- participants with low capacity have a hard time ignoring the distractors
- two items with distractors was much easier for people with high capacity
- high working memory is linked to an ability to direct attention where we want it
- the amount of information we can hold in working memory may be linked to how well we direct external attention
what is overt vs. covert attention?
- overt: attention allocated by moving one’s eyes toward a location
- covert: attending to an area in the periphery without actually directing gaze toward it
what are saccades?
- quick jumps as seen by looking at the eyes
- but, we don’t perceive the jumps in our vision
- similar to how we look when we read
how are saccades linked to spatial attention?
- planning a saccade to an object of interest is preceded by a shift of attention to that object
- many brain areas that are important for the control of saccades are also involved with shifts of attention
what are the key brain areas for the control of eye movements and visual spatial attention?
- superior colliculus: directing attention to salient stimuli
- pulvinar: input from fovea, fast processing
- intraparietal and post central sulci
- frontal eye field: anticipating things
where is the superior colliculus and what does it do?
- in the midbrain, on the posterior surface of the brainstem
- receives direct input from the retina
- also receives input from other sensory areas
- responsible for shifting attention and making saccades to pay attention to something
how is overt attention linked to saccades?
- overt attention is a form of spatial attention that is linked to where we look
- attention precedes an eye movement, meaning processing is already enhanced in that area before we even have a saccade
- neural control of overt attention and saccadic eye movements overlaps
what does covert attention tell us about the connection between eye movements and attention?
- covert attention means we are paying attention to a location in space that we are not looking at
- shows that attention can be decouple from eye movements
- examples: eavesdropping on a conversation while doing something else, driving
- also, even if someone is looking at something, doesn’t mean they are paying attention to it
who is marisa carrasco-queijeiro and what did she discover?
- female professor at New York University
- uncovered mechanisms that underlie the attentional modulation of visual perception
- found that attention changes the speed and accuracy that we process visual information, but also changes the appearance of visual objects
what is selection?
- singling out certain pieces of information among many
- one of the key functions of attention
what are the two ways that we can allocate overt or covert attention in a visual scene?
- voluntary attention: effortful process in which we selectively attend to goal-relevant information
- reflexive attention: allocated because a salient object/event has captured attention
what is spatial attention?
- selectively attending to a location in space
- enhances info at a specific location and suppresses info that is not at that location
- enhance: processing is faster, more accurate
- suppress: processing is slower, less accurate compared to neutral
- attentional resolution decreases as the amount of things we try to attend to increases
how can spatial attention be measured?
- commonly measured with the Posner Cueing Task
- visual cue points to a target with a certain likelihood
- valid: if the target appears at cued location
- invalid: if the target does not appear at cued location
- endogenous (central) cue: engages voluntary attention, can appear in between potential target locations and indicate where target is likely to appear
- exogenous (peripheral) cue: engages reflexive attention, can appear at one of the target locations
what are some results of the posner task?
- valid cues lead to faster responses than invalid cues
- valid cues also lead to more accurate responses
- exogenous and endogenous attention likely engage different mechanisms
- exogenous attention is transient and can be allocated much faster (2x) than endogenous attention
- different brain areas might serve these different types of attention
what different brain areas can be responsible for endogenous vs. exogenous attention?
endogenous/voluntary attention - dorsal
exogenous/involuntary attention - ventral
what is feature-based attention?
- selectively attending to an object’s or person’s feature
- “distinguish the orientation of the red object”
- increases activity in neural regions sensitive to target feature
- simultaneously activity of neurons that are sensitive to other features is suppressed
what is feature-based tuning?
activity of neurons that are sensitive to a target feature is enhanced
what is temporal attention?
- selectively attending to an event in time
- “press the button when you hear a beep”
- temporal properties of attention are important in shaping what we become aware of
what is attentional blink?
effect in which the second of two targets in rapid succession of items is more difficult to detect than the first
- seems to be a bit of a refractory period after attending to the first target that makes it harder to attend to the second target
what is object-based attention?
- selectively attending to a particular object
- attention to one part of the object entails attention to the whole object
how do brain lesions show us that we attend to whole objects?
- patients with right parietal lobe lesions show spatial neglect
- they are unable to process information presented in the left visual field
- some patients show object-based neglect and are not able to process the left side of any object, even when it’s shown in the right visual field
what is the biased competition model of attention?
- stimuli in a cluttered environment compete to drive the responses of neurons in the visual system
- each neuron responds optimally to stimuli in it’s receptive field
- visual stimuli that fall within the same receptive field create the most competition for attention
how does the biased competition model of attention claim that we see two stimuli that are in competition?
- selective attention biases the competition in favour of one stimulus over others
- either through top down process (favours goal-oriented stimulus) or a bottom up stimuli (favours more salient stimulus)
- competition for neural processing occurs through the visual cortex
- signals that bias (resolve) the competition are thought to come from brain areas in frontal and parietal cortex that are related to attentional control
what is early vs. late selection?
at what time during the flow of visual information processing does attentional selection occur
- early selection: we attentionally select stimuli based on physical features (colour, pitch, location) then register their meaning after we selected them
- late selection: we process the meaning of everything around us before we select items that will gain heightened awareness (also called preattentive processing)
- attention can operate both early and late
what task is used to see whether information is processes serially, or in parallel?
visual search tasks where the person has to find a target in a set of distractors
what are the different types of visual search tasks?
- simple feature search: target is salient, one white square among black circles
- conjunction search: lots of distractors, one white square among white circles and black squares
what do the different visual search tasks tell us about serial and parallel processing of visual info?
- when a target pops out, detection is quick regardless of search array’s size
- this is proof of parallel processing
- when the target is harder to find (characterized by a conjunction of features), search time increases as the search array increases
- proof of serial processing
what is feature integration theory?
- during preattentive processing, we do not perceive individual objects but rather, a “jumble” of colours and shapes
- process happens early, automatically, fast, and in parallel
what is the binding problem in the feature integration theory? what is the solution?
- binding problem: How do we combine these features, which are all processed in different brain areas?
- focusing attention on an object binds features together, allowing perception of a meaningful object
what are the stages of feature integration theory?
stage 1 - preattentive stage: different brain areas automatically gather info about basic features found in visual field
stage 2 - focused attention: object is selected and attended to within a master map of locations
- attention helps to combine individual features of this object, attended features are stored in object files
what is broadbent’s filter model?
- attempts to pinpoint the stage of processing at which information gets selected
- information is attended or ignored based on early stimulus characteristics before the semantic meaning of the info is processed
- process of info getting into sensory store is bottom up, then process of selectively filtering based on characteristics is top down
- claims that nothing we don’t attend to comes into conscious awareness, which is not true
what is treisman’s attenuator model?
- extension of broadbent’s model
- attentional selection initially occurs based on early, physical properties but does not eliminate processing of unattended information
- rather than being ignored or suppressed, unattended information is dampened
- meaningful unattended information can still reach awareness
what is load theory?
- attentional selection depends on how demanding the attended task is
- with a “high load” task that takes up attentional resources, unattended info is filtered out early
- with a “low load” task that does not need attentional resources, unattended info can take some attentional resources, be analyzed more, reach awareness, and interfere with the task at hand
what is attentional modulation?
when attention changes the way we perceive a stimulus
what are some ways that attention modulates our perception?
attention…
- increases perceptual sensitivity (performance accuracy)
- increases perceptual processing speed (performance speed)
- alters perceptual appearance, object might look higher in contrast when attended to
what is vigilance?
- a state of heightened attentional anticipation
- people are able to prepare themselves to allocate attention when they are given a cue that a simulus will appear
- continuous performance tasks require continuous vigilance
- ex. working as an air traffic controller or anesthesiologist
