26.3 - Constraints on Cognition: Human Attention Flashcards
1
Q
What are the different types of attention?
A
- Selective attention -> Filtering out irrelevant information to focus on the relevant
- Sustained attention -> Maintaining processing on a certain goal for a long period of time
- Executive control over attention (a.k.a. cognitive control) -> Maintaining focus when the response is not the automatic one (i.e. things are getting difficult)
The spec mentions spatial attention and selective attention.
2
Q
What is spatial attention?
[IMPORTANT]
A
Spatial attention involves selecting a stimulus on the basis of its spatial location.
3
Q
What is selective attention?
[IMPORTANT]
A
Filtering out irrelevant information to focus on the relevant.
4
Q
What are the main types of disorders of attention?
A
- Developmental
- Attention Deficit Hyperactivity Disorder (ADHD)
- Degenerative
- Parkinson’s disease
- Alzheimer’s disease
- Disorders in young adults
- Traumatic brain injury
- Schizophrenia
- Attention lapses (in all people, even without disorders)
5
Q
Give an example of selective attention.
A
Our bodies sense lots of touch stimuli, but we filter out lots of these, such as the rubbing of clothes against our skin.
6
Q
What is the consequence of selective attention?
A
We can fail to be aware of things that our brains see.
7
Q
How can selective attention be demonstrated?
A
Using change blindness demonstrations:
- Two pictures with a very small difference are shown very quickly one after the other
- The viewer is unlikely to be able to notice that difference due to more interesting things happening in the photo
8
Q
What is the clinical relevance of dealing with patients with attention disorders?
A
Much of the information given to patients will not be encoded well, especially if they have attention disorders. So it is worth speaking slowly and clearly, emphasising the important information.
9
Q
What are the two ways in which selective attention can work?
A
- Bottom-up (stimulus-driven)
- Top-down (goal-driven)
10
Q
Give an example of bottom-up selective attention.
A
- This is where a sudden change in your visual field catches your attention.
- For example, a brick being thrown is likely to capture your attention.
11
Q
Give an example of top-down selective attention.
A
- This is where our processing is selectively directed towards certain information.
- For example, if you are looking to meet a friend wearing a red coat, you can scan the crowd looking at just the red parts of the crowd.
12
Q
Give some examples of ways in which we can study spatial selective attention. Name a paper that studies each of these.
A
- Track where we look (gaze direction)
- Provides a measure of what has captured attention in the visual scene, bottom-up or top-down (Yarbus).
- Show that it is possible to enhance perception
- If attention is deployed to a location, perception should be enhanced there – but at a cost of reduced perception at other spatial locations (Helmholtz).
- Measure how long it takes it to detect a target
- This should be faster if attention is already deployed at the location a target is presented (Posner) or when there are fewer distracting stimuli (Treisman)
13
Q
Explain Yarbus’ studies about spatial selective attention.
A
(Yarbus, 1967):
- Showed subjects this patients and tracked their eyes to see where they looked
- Without any prompt, this allowed it to be seen where top-down attention draws our eyes to (e.g. faces, clothes etc.)
- When prompted with tasks like “assess the ages of the individuals”, the eye movement is much more restricted to just faces, etc.
14
Q
Explain Helmholtz’s studies about spatial selective attention.
A
(Helmholtz, 1867):
- Had a chart of different letters, with a cross in the middle
- Focused his eyes on the centre cross, but diverted his attention covertly to a corner of the chart (without changing his gaze)
- His recollection of the letters in that corner improved, but worsened in other corners
- This illustrated that attention can be separated from vision and that focusing our attention on certain stimuli improves our perception of them, but it is at the cost of worse perception elsewhere
15
Q
Explain Posner’s studies about spatial selective attention.
A
- Used a setup with a central cross and a box on either side
- The subject is told to look at the central cross
- One of the boxes lights up yellow as a “cue” for which box will light up next -> The subject can see this cue in their peripheral vision (covertly moving their attention there without moving their eyes)
- The cue is correct about 80% of the time
- Next, one of the boxes lights up blue and the subject needs to press a corresponding button as quickly as possible
- When the cue is correct, the response time is much faster than when the cue is incorrect, since the subject must shift their covert attention, which takes time
- The difference in time is the invalidity cost
16
Q
Which parts of the brain are involved in shifting human attention overtly (via eye movement) and covertly?
[IMPORTANT]
A
- Superior parietal lobe
- Intraparietal sulcus
- Frontal eye fields
17
Q
Explain Treisman’s studies about spatial selective attention.
A
- Treisman used visual search tasks, where a subject looks for a certain object within a field of distractors
- When the subject looks for a green T in a field of red Ts, this is known as a feature search -> It is almost immediate and the time to find the T does not vary with the number of objects in the field
- When the subject looks for a horizontal green T in a field of horizontal/vertical red Ts and verticl green Ts, this is known as a conjunction search -> It is slower and the time to find the T increases with the number of objects in the field. This is because the attention must shift between objects and each one must be analysed, which takes time.
18
Q
Describe Treisman’s feature integration theory.
A
(Treisman, 1980):
- Suggests that there are various feature maps in the brain, such as for colours, orientations and motion -> These are pre-attentive
- This means that if you are looking for a red shape among green ones, it is easy and fast because you can do it all within these feature maps
- When looking for a conjunction of features (such as a red shape on its side), the brain moves an attentional spotlight across the retinotopic mapping in the brain and looks to see if the features exist in combination at that spot -> This is called feature binding
- In other words, conjugation search is much slower because it requires combination and processing of information
- This integration might occur in the parietal lobe
19
Q
Give some experimental evidence for feature binding.
[EXTRA]
A
- A patient who has Balint syndrome, with bilateral parietal lesions, may experience problems with feature binding
- In these cases, the patient may frequently confuse the colours of two letters that are shown next to each other
20
Q
What are the disorders of attention mentioned in the spec?
[IMPORTANT]
A
- Extinction
- Unilateral neglect
- Goal neglect / Dysexecutive syndrome
21
Q
What is simultanagnosia and who studied it?
A
- It is the inability to perceive more than one object at a time
- Balint studied this -> He had a patient with bilateral stroke of the parietal cortex, who struggled to see perceive more than one object at a time.
- Luria also studied this -> He showed his patients a star drawn using two differently coloured triangle and the patients could only perceive one of the triangles when looking at it.
22
Q
What is visual extinction?
[IMPORTANT]
A
- A disorder that occurs after damage to the parietal lobe
- The patient is able to perceive stimuli on their own in any part of the visual field
- However, they cannot perceive a stimulus on the contralesional side if it is presented alongside a stimulus on the ipsilesional side
23
Q
What is unilateral neglect?
[IMPORTANT]
A
- When a patient has unilateral damage to the parietal lobe, resulting in inability to perceive any objects on the contralesional side of the visual field.
- For example, when drawing an object, the patient may only draw half of the object.
24
Q
Which parietal cortex is more commonly lesioned in unilateral neglect?
A
Right
25
Do attention disorders usually feature lesions of the early visual centres?
No, it is usually later than that. The patient can usually see everything fine, just can't perceive it.
26
Why do right hemisphere strokes lead to more profound unilateral neglect?
The left hemisphere is more concerned with speech and language.
27
If a stimulus activates the primary visual cortex, does this mean it will be perceived?
* No, because attention disorders can cause a lack of perception, so the stimulus is not consciously perceived (Rees, 2000).
* This can be studies using fMRI.
28
Give some interesting experimental evidence for unilateral visual neglect.
(Halligan, 1988):
* Showed patients with unilateral neglect two pictures of houses, one of which is burning
* They asked the patients to select the house they would prefer to live in
* 80% of patients selected the non-burning house because it looked nicer, despite not being able to identify that the other house was burning
* Thus, this implies that visual information may influence our biases, even if it is not consciously perceived
29
Give some experimental evidence surrounding how sustained attention changes over time.
* Macworth studied the attention of radar operators over time
* The graph showed how this attention declined with time spent at the radar
30
Which parts of the brain are involved in sustained attention?
[IMPORTANT]
* Right frontal
* Right parietal
31
Can unilateral neglect be treated?
* Patients may improve scanning to the contralesional side on the training tasks, such as identifying bright flashing lights
* But this does not 'generalise' to other tasks in everyday life
32
What are some drugs that may improve attention?
[EXTRA]
* Methylphenidate (ritalin) and amphetamines
* Modafinil
* Donepezil
33
What lesions may cause problems with executive control over attention (a.k.a. cognitive control)?
Frontal lobe
34
Give an example of a test that may be used to test executive control over attention (a.k.a. cognitive control).
* Stroop test
* In this test, executive attention must be used because the words do not correspond to the colours, so normal reflex reactions to reading them do not work and must be overcome
35
What is dysexecutive syndrome and what causes it?
[IMPORTANT]
* It is a lesion of the frontal lobe
* It features impaired executive functions, including the planning, focusing attention and behavioural
* An example of symptoms is that the patient may struggle with the Stroop test
36
What is the difference between:
* Simultanagnosia
* Unilateral neglect
* Visual extinction
* Dysexecutive syndrome
* Simultanagnosia -\> Cannot perceive more than one object at once, anywhere in the visual field
* Unilateral neglect -\> Cannot perceive stimuli on the contralesional side
* Visual extinction -\> Cannot perceive a stimulus in the contralesional field WHEN an stimulus is also shown on the ipsilesional side
* Dysexecutive syndrome -\> Problems with executive control
37
How are attention and sensory stimuli related? Give some experimental evidence.
[IMPORTANT]
(Veldhuijzen, 2006):
* Had subjects perform high attention load and low attention load tasks while being subjected to painful stimuli.
* Results indicate that highly demanding attentional task performance and pain processing interfere as a result of difficulties in allocating attention.
Furthermore, decreased attention can lead to sensory loss and leave the individual with a reduced ability to recognise inputs, potentially causing them to miss vital information that would improve outcomes.
38
How are attention, planning and intelligence related?
[IMPORTANT]
There are strong links between attention, short term memory, and planning ability through executive control, as well as better attention usually linking to improved outcomes and completion of tasks that can make an individual seem intelligent.
39
Summarise which brain areas are involved in attention.
* Right inferior parietal lobe
* Responsible for spatial processing in attention
* Lesions lead to neglect of the left visual field, despite the eyes and visual cortex being intact
* Frontal lobe
* Responsible for executive control over attention (top-down hypothesis)
* Lesions can lead to poor scores on the Stroop colour and word test as a result of decrease attention to the contents of the visual field
* Right frontal and parietal lobes (again)
* Involved in sustained attention (staying focused on a task in the long-term, driven by goal-motivated behaviours)
* Frontal eye fields
* Involved in shifting attention using the gaze
