Attention

Question 1

What are the types of attention?

Answer 1

1. Overt attention
2. Covert attention

Question 2

What is overt attention?

Answer 2

Physical turning of head and eyes in order to preferentially process an object/region of visual space.

Question 3

What is covert attention?

Answer 3

Preferentially processing objects in visual space without moving the eyes.

Question 4

What is the dichotic listening test (Cherry, 1953)?

Answer 4

• Subjects were played 2 different auditory messages simultaneously, one in each ear.
• The subjects were asked to selectively attend to message in one ear by repeating it but ignore the message in the other ear.

Question 5

What were the results of the dichotic listening test?

Answer 5

• The contents of the unatteded message were not remembered, despite the contents of the attended message being remembered.
• The characteristics of the unattended message were remembered, including:
  1. Pitch
  2. Volume
  3. Location
• This is not overt attention as both messages were simultaneously presented, but the subject selectively only processed message in one ear.

Question 6

Why did behaviourism delay study of covert attention?

Answer 6

• Covert attention is a purely internal process, with no external observable counterpart.
• This went against the ethos of behaviourism.

Question 7

What was Broadbent’s filter model of attention?

Answer 7

• All information passes through ‘bottleneck’ that filters it and selects the information that goes on to be processed.
• This is all-or-nothing, so that only physical attributes of the discarded information is processed and nothing else.

Question 8

What is the filter-attenuation model of attention?

Answer 8

Information not attended to is not completely discarded (i.e. not completely unprocessed). Instead, it is simply attenuated so that less processing power is dedicated to it, but it is processed none-the-less.

Question 9

What evidence goes against Broadbent’s filter model and supports the filter-attenuation model?

Answer 9

• Treisman (1960): When message that was being selectively attended to switched ears, the subjects were able to also switch ears to maintain attention.
• Cherry (1953): When subject’s own name appeared in the unattended message, he/she would still notice it.
• Von Wright et al. (1975): Words conditioned to be associated with electric shocks still produced Galvanic skin response (i.e. fear response) when played on the unattended channel of the dichotic listening test.

Question 10

What was Posner’s experiment?

Answer 10

1. A target was presented on either the left or right-hand side of the screen.
2. A cue was presented at the centre of the screen:
   - Valid cue: Cue correctly indicated position of target
   - Neutral cue: Cue did not predict the position of target
   - Invalid cue: Cue incorrectly indicated position of target

Question 11

What were the results of Posner’s experiment?

Answer 11

• Subjects presented with valid cue were the fastest to respond to the target
• Subjects with invalid cue were the slowest to respond to the target
• Indicated that there was a physical process of shifting attention that took time

Question 12

What is the “spotlight metaphor” for attention?

Answer 12

Attention is like a spotlight. Everything positioned within the circle of space in the spotlight of attention was processed while everything outside was not processed, regardless of the actual characteristics of the objects in the spotlight (i.e. no object perception needed).

Question 13

What are exogenous cues for attention?

Answer 13

External indicators of attention that indicates in physical space where attention should be drawn (i.e. shining light into spot where attention is needed).

Question 14

What are endogenous cues for attention?

Answer 14

indicators of attention that symbolise where attention should be drawn but require cognitive decoding of semantics in order to do so (i.e. arrow pointing in direction attention should be drawn).

Question 15

What neurobiological evidence is there for attention?

Answer 15

fMRI studies have shown that certain areas of the cortex are more active when attending to specific types of stimuli (moving or static) compared to when not attending to it. This suggests attention acting as a kind of ‘gating mechanism’ for attention.

Question 16

What evidence is there against the “spotlight metaphor” in support of idea that object perception is important in attention?

Answer 16

1. Egly et al (1994): 2 cues were presented to subjects equidistant from a fixation point. The only difference being that cue 1 was on the same object as fixation point while cue 2 was on different object.
2. Scholl & Phylyshyn (1999): Subjects were asked to track a number of moving dots on a screen. The dots occasionally moved behind 2 types of bars in 2 separate tests:
   - Continuous existence: Bars were visible (dots vanished behind bars)
   - Discontinuous existence: Bars were invisible (dots disappeared from existence)

Question 17

What were the results of Egly’s same/different object attention experiment?

Answer 17

Experiment found that subjects were faster to attend to cue on same object.

Question 18

What were the results of Scholl & Phylyshyn’s dot tracking experiment?

Answer 18

• Dots were easier to track when they were in continuous existence compared to when they vanish out of existence
• Implies that attention is based on the dots themselves as opposed to the region of space the dots occupy

Question 19

What is unilateral neglect syndrome?

Answer 19

• Patients ignore objects on one side of the visual space and are unable to attend to them
• Patients also ignore features on the same side of an object being attended to

Question 20

What clinical tests can be used to test for unilateral neglect syndrome?

Answer 20

1. Asking patient to draw object (e.g. clock). Patients with condition often draw one side well but the other side poorly (if at all).
2. Asking patients to find specific features in a picture. Patients find all features on one side, but ignore the other.
3. Asking patients to bisect lines off centre relative to the centre of the page. Patients often bisect lines tending towards neglected side poorly.

Question 21

What causes unilateral neglect syndrome?

Answer 21

• Unilateral damage to parietal lobe (at temporo-parietal junction) causes neglect affecting contralateral side of visual space.
• Damage to frontal lobe and subcortical areas.

Question 22

What is unilateral extinction?

Answer 22

• Patients are able to perceive objects on affected side of visual space when presented alone, but are unable to when another object is presented in unaffect side.

Question 23

What causes unilateral extinction?

Answer 23

Unilateral damage to parietal lobe causes extinction affecting contralateral side of visual space.

Question 24

What type of bias exists in neglect/extinction?

Answer 24

Most patients present with affected left side

Question 25

What is a possible explanations for bias towards left-sided attention bias syndromes?

Answer 25

1. Attention processing for the left visual space is handled by the right hemisphere only while attention processing for right visual space is handled by both the right and left hemispheres. 2. There is interhemispheric competition for attention and the hemispheres co-inhibit each other, but the left hemisphere is dominant and has greater inhibitory effect. When right hemisphere damaged, there is greater inhibition from left hemisphere (dominant hemisphere) than there is from the right if left hemisphere is damaged, so only left-sided neglect is evident.

Question 26

What are the symptoms of Balint's syndrome?

Answer 26

1. Simultanagnosia: Failure to perceive multiple objects simultaneously 2. Oculomotor apraxia (fixity of gaze): Difficulty diverting overt attention quickly between objects 3. Optic ataxia: Inability to guide hands towards an object using visual cues.

Question 27

What causes Balint's syndrome?

Answer 27

Bilateral damage to parietal lobes

Question 28

What is the purpose of attention?

Answer 28

Enhancing the processing of relevant information by enhancing activity of areas of the brain involved in processing particular sensory information.