6 - Attention: Structure, Capacity and Control

Question 1

What was the Early Selection Reply to Late Selection Theory?

Answer 1

• LS argued that semantic activation on the unattended channel is evidence of a downstream filter.
• ES reply: weak semantic activation on the unattended channel is actually consistent with the attenuated channel 2 postulate of the early selection theory.

Question 2

Describe Moray’s (1970) Cost of Divided Attention experiment.

Answer 2

A dichotomous listening task with brief auditory tones (beeps) - target tone was a slightly louder beep.

3 Conditions:

• Selective: pts monitor for targets on one channel only - 67% correct - focused attn.
• Exclusive Or (XOR): Monitor both channels, no simultaneous targets - 54% correct - divided attn.
• Inclusive OR (IOR): Monitor both channels, simultaneous targets possible - OR trials 52% AND trials 31% correct - large cost of simultaneous detection.

Summary of effects:

• Compare simultaneous targets (AND trials) and nonsimultaneous (OR trials):
  
  • Moderate cost of divided attention (OR < SEL)
  • Large cost of simultaneous detection (AND < OR).
• The largest cost of divided attention is seen when monitoring of simultaneous channels in AND trials.

Question 3

What are the implications of Moray’s study on Early Selection & Late Selection Theories? How do their findings map each? Which does it support?

Answer 3

AND = target stimulus on both ears at the same time.

OR = divided attention - target on one ear or other.

SEL = selective attention - target on one ear only.

Early Selection:

• Predicts OR < SEL: because attenuation (cost) with divided attention.
• Doesn’t predict AND < OR: because attenuation shouldn’t depend on identity of stimulus.
  
  • Two targets at once should not cause further attenuation.
  • Because filtering occurs before target/nontarget distinction is made.

Late Selection:

• Predicts AND < OR because two simultaneous targets will both be selected by “pertinence” (top-down) & get through the filter.
• Doesn’t predict OR < SEL because if there aren’t two targets, no competition - target gets through the filter.

SO… not entirely consistent with either

Question 4

What is the difference between structural (bottleneck) theories & capacity (resource) theories?

Answer 4

Structural (Bottleneck) Theories

• Some neural structures can only deal with one stimulus at a time
• Competition produces processing “bottleneck” (filter theory)
• (ES: bottleneck getting into LTM; LS bottleneck getting out)

Capacity (Resource) Theories:

• Information processing is mental work
• Work requires activation of neural structure
• Limited capacity to activate structure

Question 5

What is the key idea behind Kahneman’s (1973) Capacity Theory?

Answer 5

• Reduction of capacity produces deficit in divided attention tasks
• Differs from structural theories because capacity can be allocated flexibly to simultaneous tasks

Question 6

How did Strayer & Johnston (2011) show the effects of divided attention interference for the talking on the phone-driving task?

Answer 6

Talking on a mobile phone interferes with driving (sharing capacity reduces accuracy and increases RT)

• 100 ms @ 60 km/h ~ 1.7 m

Question 7

How did the Dual Task Performance (Li et al., 2002) offer evidence of capacity theory?

Answer 7

• Attention demanding central task (letters same or different?)
• Easy or hard peripheral task (animal present? “Phase” of disk?)
• Difficult task much more affected by central load

Question 8

How does Capacity Theory explain “inattentional blindness”?

Answer 8

• Cartwright-Finch & Lavie (2007) – which arm of flashed cross is longer?
• Clearly visible square not detected
• Demanding central task uses all available capacity - none left for anything else.

Question 9

How is capacity studied by dual task trade-offs? Describe attention operating characteristic (AOC), proportion, and graceful degradation.

Answer 9

• Attention operating characteristic (AOC) - visual, auditory etc.
• Vary proportion of attention allocated to two tasks in the paradigm - attend to task 1 100%, T1 75% & T2 25%…
• You’ll see a “graceful degradation” of performance as available capacity is reduced.
• The shape of trade-off curve tells us about the capacity demands of the tasks. (Y-axis is task 1 / X-axis is task 2).

Question 10

What did Bonnel & Hafter’s (1998) Auditory and Visual Dual Tasks show about capacity demands of hard and easy tasks?

Answer 10

Two Tasks:

• detection task (easy)
• discrimination task (hard)

Conditions

• Attend to the visual task or the auditory only.
• Divide attention between them.
  
  • 80/20, 50/50, 20/80 etc

Findings:

• Hard task: expect inverted-U trade-off curve.
• Easy: No trade-off curve.

Inference: tasks require different capacity demands.

Question 11

What are the pros & cons of Capacity Theory?

Answer 11

Pros

• Led to new experiments.
• Emphasises divided attention, flexibility of attentional control.

Cons

• Vague

Question 12

What is Posner’s “Spotlight of Attention?

Answer 12

• Shifts of attention likened to moving spotlight
• Selective enhancement for stimuli “illuminated by the beam”
• Expresses selective, limited-capacity idea in spatial terms

Question 13

What’s the basic idea behind Posner’s Spatial Cuing Paradigm?

Answer 13

Attract attention to A, present stimulus at A or B, compare performance.

Design:

• Cue Field & Wait for specified SOA (stimulus onset asynchrony) 100-300ms
• Present stimulus & Measure detection RT
• Cued (valid) trial: stimulus occurs at attended location
• Miscued (invalid) trial: stimulus occurs at other location (with low probability).
• Uninformative/Neutral cue: 2 arrows 50/50 cue - baselines to compare valid & invalid trials against.

Question 14

What are the attentional costs & benefits of Posner’s Spatial Cuing Paradigm? What are the causes of cuing effects?

Answer 14

Results:

• Benefits: Faster RT with valid cue
• Costs: Slower RT with invalid cued
• Very flexible: can be used with RT or accuracy, and to compare all kinds of stimuli.

Causes:

• Switching times - time to move the spotlight
  
  • Costs of disengaging from wrong location, benefit from engaging at correct location before stimulus
• Unequal Capacity Allocation
  
  • RT depends on capacity allocated to location
  • Neutral: capacity spread across locations; focused: capacity concentrated on one location

Question 16

What are the two types of orienting attention systems and how do they differ?

Answer 16

1. Endogenous (voluntary)
   
   • cognitive, need to interpret,
   • e.g. central (symbolic) cue.
2. Exogenous (reflexive)
   
   • direct, spatial,
   • e.g. peripheral (spatial) cue

Question 17

What is the evidence for separate orienting systems in terms of:

1. Different time course ofcuing effect for central and peripheral cues?
2. (Jonides, 1981) Different effects on capacity demand?
3. Inhibition of Return.

Answer 17

1. Peripheral effect peaks rapidly, central effect peaks slowly
   
   • i.e. endogenous system (central) is slower because it’s more mental work but last’s longer..
   • Exogenous system (peripheral) is slow and dissipates quickly.
2. Different effects of capacity load:
   
   • primary memory task 1 - retain digits in memory.
   • secondary orienting task 2 - detect spot of light cue/uncued location
   • Voluntary orienting slowed by memory load; reflexive orienting is not.
3. Usually, peripheral cue benefits target detection but only up to 150ms
   
   • Inhibition of Return - after 150ms - there are costs to target detection.
   • Found only with peripheral cues, not with central cues​.
   • Inhibition of return tags location - repels attention away from “searched areas”.