Chapter 4 Flashcards
In a dichotic listening paradigm what attribute of the unattended stream can participants identify?
Physical attributes; whether its human speech, music or silence. Whether the voice is male/female, loud or quiet, high or low
They can NOThowever identify any semantic content
explain the experiment that demonstrated the same effects shown in the dichotic listening paradigm using visual inputs?
Subjects were told to focus on the white team passing a ball and ignore the black team. They did this successfully but failed to notice that a gorilla walked through the scene.
What’s the cocktail party effect?
When salient information in the unattended channel can leak through and be noticed. Similar to when you’re at a party and someone in another conversation you weren’t listening to says your name and catches your attention.
explain the bottleneck theory of attention
People erect a filter to block out potential distractors while allowing desired information to go on and receive further processing
What is a mask
Meaningless jumble designed to interrupt further processing
What is inattentional blindness and which experiment first demonstrated it?
The inability to see something directly in front of you because you aren’t paying attention to it
> first shown in an experiment by Mack and Rock where participants fixated on a target but were told to make judgements about a + elsewhere on the screen, on the 4th trial the target changed into a shape. Participants with no warning of this change didn’t notice it.
What is a real life example of inattentional blindness
Not being able to find the ketchup even though it’s right in front of you
What do Mack and Rock argue about attention?
There is no conscious perception without attention
explain the experiment that proved unconscious perception is possible without attention?
Subjects had to identify which of 2 lines was longer. On the 4th trial the dots in the background created the Muller-lyer illusion. Subjects did not perceive the pattern however they were still influenced by the illusion and said the line with the outward fins was longer although the lines were actually identical
Define change blindness and give examples
Observer’s inability to detect changes in scenes they’re looking at directly
ex. changes in two pictures, in different angles of a film, in real life (the door switch)
What are the two ways to think about inattentional blindness and change blindness
- they reveal genuine limits on perception (people don’t see the stimulus)
- they reveal limits on memory (people see it but immediately forget)
explain the early and late selection hypotheses
Early selection: Attended input is identified and privileged from the start
Late selection: All inputs receive relatively complete analysis and selection is done after
Evidence for late selection
the muller lyer inattentional blindness experiment
Evidence for early selection
- Brain activity for attended vs. unattended inputs are distinguishable 80ms after presentation while early sensory processing is underway
- Neurons in V4 are more responsive to attended inputs vs. unattended inputs
What does the evidence supporting early selection tell us about attention and perception?
Attention doesn’t change what we remember it can literally change what we percieve
How can we explain the mixed results supporting both early and late selection?
If the attended stimuli is complex fewer resources are left to process unattended stimulus showing the pattern for early selection, if the stimulus is simples more resources are available to process unattended info and the late selection pattern emerges.
How can detectors be used to explain inattentional blindness, selective listening and leaking of info from the unattended stream
inattentional blindness: If we not primed (warned) that a change will occur the detectors are unprepared and thus do not fire
Selective listening: the detectors for the distractor stream recieve no resources and are thus unprimed
Leakage: The detectors for personally salient info (ie. your name) are already primed, the activation level is higher so they will fire although your attention is elsewhere
Perception requires primed detectors, What are the two types of primes
- Stimulus based: Stimulus you’ve already encountered (recently/frequently) not under conscious control.
- Fast (immediate)
- Free (can prime one detector without taking activation from another) - Expectation Based: You can deliberately prime detectors for stimuli you are expecting
- Slower (half a second)
- Has a cost when mislead (priming the wrong detector takes something away from the others)
What does expectation based priming reveal (as shown my Posner and Snyder)?
The presence of a limited capacity system (perceiving requires work, work requires limited mental resources)
Define spatial attention
Ability to focus on a particular position in space and be better prepared for any stimulus that appears there
In Posner and snyder’s letter detection task what was revealed
Even in simple tasks, being primed to focus attention to one side of the screen means they devote less attention to the right and thus have slower RTs. = further evidence of limited capacity system
How can we be sure it’ attention moving and not the eyes?
Because eye movements require 180-200ms and benefits of primes are detected within 150ms
What group of brain areas control attention
A network of brain sites in the frontal and parietal cortexs
What area of the brain controls memory allowing you to focus on remembered events
The parietal cortex
If there is no actual spotlight beam what is there?
Neural mechanisms in place that allow you to adjust your sensitivity to certain inputs
What is unilateral neglect
A syndrome resulting from damage to the parietal cortex which causes victims to ignore all input from one side of the body
(typically there is damage on the right side and thus neglect on the left)
What symptoms of unilateral neglect support a space based approach to attention
Their inability to read the left half of words
What symptoms of unilateral neglect support an object based approach to attention
Patients who ‘lock in’ on a stimulus (the right half of a barbell) will continue to focus on it when the object rotates to the “neglected” side
Which experiments in non brain damaged subjects supports spaced based attentional bias
Posner et al. ‘s experiments in which subjects fixate on a central target and the stimulus can appear on the L or R. They are given neutral, accurate or neutral warnings. Results show the pattern in which high validity trails when the subjects are misled RT is 12% slower!
Which experiments in non brain damaged subjects supports an object based attentional bias?
- Neisser et al:superimposing to TV shows on one screen and having subjects focus on one
- Edgly et al’s experiment with two rectangles and cues appearing in either the top of bottom. There was a larger cost when the misleading cue was in the wrong rectangle than when it was in the same triangle, even though the distance was the same
So is attention object based or space based?
It’s a mix of both
What is set size and when is it a problem?
Set size is the amount of stimuli participants must search through to find a target
- Set size has no effect in single feature searches
- In targets with a combination of features participants must focus their spotlight on one item at a time, meaning set size determines the speed of the search
What are the two mechanisms involved in selective attention
- one serves to inhibit undesired input
2. one facilitates processing of desired input
When will divided attention suceed?
When the tasks are very different so they don’t compete for resources
What did the Allport et al study show about divided attention
While simultaneously shadowing words participants did poorly when memorizing words they heard in the other ear, better when seeing the list of words, and even better when the words were in picture form
> the more different the tasks the more sucessfull divided attention
In what situation do tasks using simingly different resources interfere
When they use general resources, such as driving and talking on the phone
Define response selector
A general resource/mental tool that plays a key role in coordination and timing of various activities
what are “executive functions”?
the mechanism that sets goals, chooses strategies and directs many cognitive processes
What is the proposal about how executive function works
When you wish to behave differently in a situation than you have in the past your executive functions
a) maintain the desired goal
b) inhibit the automatic responses
What is perservation error + example
A perseveration error - Maintaining the same response despite knowing the task requires a change in response
ex Patients with PFC injuries are unable to override their original strategy of sorting a deck by color and can’t switch to shape when asked
What is goal neglect, example
Failing to organize behaviour towards a goal
ex. PFC lesion patients trying to copy an image show no order of any sort in their strategy, or they simply forget the task and draw it the way they want
What are the three general resources that are drawn on in any task
- an energy supply
- A response selector
- Executive control
why does practice make divided attention easier?
Because with practice the need for executive function goes down because you develop habbits and the need for the reponse selector goes down because instead of needing to launch a series of steps you simply launch a sequence
Why does performance on single tasks improve with practice?
Because every task is made of components and at the beginning each requires resources taking them away from other higher level elements. with practice less resources are devoted to lower level elements (steering) and resources can be given to broader elements(speed, directions etc) !
What are the disadvantages of practice causing tasks to be automatic? example?
They require no mental resources and as such are uncontrollable and can’t be turned off!
ex. The stroop effect (or interference)
How can we think of attention?
as an achievement! Yay I did it!
what is treisman’s attenuation theory?
filtering based on physical properties, unattended message is weakened not blocked
WHo advocates for the early selection and who advocates for late selection
Early : Broadbent
Late: Deutch & Deutch
What did treisman and Mckay show about info leaking from the unattended stream?
Treisman - when the second half of a sentence is in unattenuated ear subjects unconciously switch over
Mckay - Words in the unattended stream can influence comprehension of words in the attended stream
What is negative priming?
When you ignore one stimulus in a trail and are told to attend to it in the next one
What is the psychological refractory period
period of time during which the response to a second stimulus is significantly slowed because a first stimulus is still being processed.
What is the Unitary tool Hypothesis
The second task has to wait until the first task has finished with the response selector!
Can we do response selection simultaneously?
NO
What are the 2 kinds of practice in visual search?
Consistent mapping: Targets and distractors are never drawn from the same set of letters
Varied mapping: Targets and distractors are drawn the same set of letters
Did set size have an effect after subjects engaged in either type of visual search practice?
In consistent mapping - they were just as fast for set of 3 as a set of 1, in this case executive control is not needed
In varied mapping - Showed a set size slope because they continued to do a serial search meaning automaticity cannot develop
What happens if you reverse which letters are targets and which are distractors?
Subjects who recieved consistent mapping practice did very poorly because it’s hard to overcome automaticity - they need the central executive control
Define channel segregation
Keeping the inputs and outputs of two tasks seperate
Define Crosstalk
Mixing the two channels and preventing concurrent performance
What are the characteristics of Directed attention?
- Endogenous (from within)
- “controlled”
- Top-down - conceptually driven- process
What are the characteristics of Captured attention?
- Exogenous (from outside)
- “Automatic”
- Driven by bottom up - data - driven processes
