Mechanisms of selective and divided attention

Question 1

What is attention? - Sternberg 1999

Answer 1

Attention acts as a means of focusing limited mental resources on the information and cognitive processes that are most salient at a given moment

Question 2

Describe attention as a mental process

Answer 2

Concentrating effort into a stimulus or a mental event (thought)

• Forcing yourself to pay attention in this lecture is an example
• The means by which we actively process information in the sensory registers (sensation caused by light hitting the eyes, in the case of perception)

Question 3

Describe attention as a limited mental source

Answer 3

Attention as a kind of fuel/mental energy that powers cognition
•It gets used up when we “pay” attention
•Attention is limited

Question 4

What is attention for?- Selection

Answer 4

We are constantly presented with information from the external world

• Audition: Numerous overlapping sounds simultaneously reach your ears. The busy street; the conversation in the noisy pub
• Vision: complexity and information overload characterize most visual environments
• Your own thoughts: Even what you are thinking competes for your attention…Our attentional capacity is severely limited:

There is only so much we can attend to at one time

Effective selection of information is critical to functioning

Question 5

Division

Answer 5

Most things you do during the day involve a degree of ‘multi-tasking’
•Writing notes while listening
•Walking and having a conversation
•Watching TV while on the phone
•Listening to music while studying
•Various factors impact on our ability to divide attention Effectively dividing your attention is also critical, as is knowing the limitations

Question 6

What is selective attention?

how’s it studied?

what does it demonstrate?

Answer 6

focusing all of our attention on one task

present 2 or more stimuli and instruct to attend to one of them

our ability to select, and the fate of unattended stimuli

Question 7

what is divided attention?

hows it studied?

what does it demonstrate?

Answer 7

sharing your attention between tasks

present ppts with multiple stimuli and instruct to attend to all

the processing limitations of attention

Question 8

divided attention: task similarity

Specificity of Resources: Allport, Antonis & Reynolds (1972)

Answer 8

Presented participants with a list of words through headphones into one ear.

Task: Shadow these words

Simultaneously: Presented them with a second list.

Later on, memory tested for items for second list

Question 9

The specificity of Resources: Allport, Antonis & Reynolds (1972) - conditions

Answer 9

The second list presented to the other (unattended) ear.

The second list presented visually on a computer screen.

The second list consisted of images presented visually on screen

Question 10

Requirements similar, but task similarity varied

Answer 10

Hear words + hear words = high similarity
Hear words + see words = less similarity
Hear words + see images = low similarity

Modality specific resources: Most interference should come from condition 1, and least from condition 3

.General pool of resources: performance should be similar in all three

Found: Most interference in condition 1; followed by 2, followed by 3

Question 11

Divide attention : practice

Spelke, Hirst & Neisser (1976

Answer 11

Difficult tasks can become less attentionally demanding through practice

Spelke et al. (1976) trained their participants (e.g., gave them practice) on two tasks that are hard to combine.

Two students were trained for 5 hours per week over a 4 month period

Task: read a story for comprehension while also writing dictation.

This was initially really hard, but after 6 weeks they could perform the task very well

Question 12

divided Attention, Practice & Automatic Processing

Answer 12

If you do a task enough times, it feels less demanding. There’s a psychological reason for that.

• Practice decreases resource demands by diminishing the need for moment-by-moment task control
• Controlled tasks draw more attention than uncontrolled tasks

.•With practice a person approaches a task with a well learned sequence of responses that they have done in the past

•A ‘routine’ like this becomes automated and no longer needs to be supervised or controlled and therefore requires fewer resources

Question 13

What Makes a Process Automatic? Posner & Snyder (1974; 1975)

Answer 13

A process is automatic if it meets the following criteria:

• It occurs unintentionally
• It occurs unconsciously(outside of awareness)
• It operates without depleting the resources of attention

Question 14

What Makes a Process Automatic? - Logan 1988

Answer 14

a task becomes automatic when practice changes it so much that it relies on knowledge stored in long-term memory

Question 15

attention & Automatic Processing

- the effects of automacity

Answer 15

Automatic processes are uncontrolled, take little cognitive effort (attention) and therefore difficult to inhibit.

Not always beneficial!

Question 16

Whats the stroop interference

Answer 16

Stroop Interference:

Show participants colour words, each printed in a different ink

Task: name the colour of the ink

Typical finding:
Facilitation when the ink and colour word match
Interference when they do not match.

Question 17

two conditions in the stroop task

Answer 17

Congruent condition and the Incongruent (conflicting) condition

Question 18

Mechanisms of Selective Visual Attention

Answer 18

Visual selective attention has been likened to a torch beam (Spatial attention: Posner, 1980).

•Information that falls under the beam is processed with priority

• Information outside of the beam receives far less processing
• Metaphors of spatial attention:
• Spotlight
• Zoom lens
• Multiple spotlights

Question 19

Change blindness - Rensink . o’Regan and Clark (1997)

Answer 19

Pairs of pictures separated by a brief blank interval

Identical except for some single aspect that is missing in one picture but present in the other

Even with clear understanding of this task, it is very hard

Question 20

Change blindness - Rensink . o’Regan and Clark (1997)

characteristics

Answer 20

If the change involves something central to the scene, observers may need as many as a dozen alternations between the pictures before they detect the change.

If the change involves some peripheral aspect of the scene, then as many as 25 alternations may be required.

Question 21

Implications of Change Blindness

Answer 21

Implication:
We see far less of a visual scene than we think we do in the absence of attention

Highlights again the limited capacity of attention: We cannot attend to everything!

These studies demonstrate failure to detect changes we are looking for

Question 22

Inattentional Blindness

Mack and Rock 1998

Answer 22

Participants presented with a large + for 200ms, followed by a pattern mask

Task: Indicate which bar was longest, using two response buttons

Maintained central fixation throughout the experiment and the + was shown off to one side

Question 23

Inattentional Blindness

Mack and Rock 1998 - results

Answer 23

Performance at detecting line length: 78% accuracy

But! On trial 4, while the target cross was on screen, the fixation target disappeared and was replaced by a shape (e.g., a triangle, a rectangle etc.).

Immediately after trial
asked if anything different had happened during this trial.

89% of participants reported no change

They had failed to see anything other than the attended + shape

To probe the participants further: told that a shape had replaced the fixation cross.

They were then asked what shape they had seen.

Found: Responses were random

Participants had not seen the shape that had been directly in front of their eyes

Question 24

Inattentional Blindness

Mack and Rock 1998 - conc and implications

Answer 24

Mack and Rock (1998): as participants were not expecting any shapes to appear they were not prepared - their attention was elsewhere (judging the lines)

• Shapes not seen even though in plain sight
• Implication: What we see is dramatically diminished in the absence of attention
• Again, demonstrates our limited amount of attentional resource

Question 25

Inattentional Blindness

Mack and Rock 1998 - claims

Answer 25

Mack and Rock (1998): without attention there is no perception

In other words, we don’t perceive things that we aren’t attending to
This is a very bold claim
Can we demonstrate perception in the absence of attention?
Bring back the Muller-Lyer illusion.

Question 26

Inattentional blindness - Moore and Egeth (1997)

Answer 26

Participants shown displays containing two horizontal lines surrounded by a pattern of black and white dots

Task: Which line is longest?

The first three trials: Background dots were random..

Question 27

Inattentional blindness - Moore and Egeth (1997) - results

Answer 27

On trial 4 the pattern of dots formed a figure like the Muller-Lyer

Participants did not perceive the dot pattern

How do we know? Asked after the trial to decide which dot pattern there had been from 4 choices. 90% got it wrong.

Finding 1: replicates inattentional blindness

Did the Muller-Lyer configuration influence performance on the line task?

Findings: 95% of participants reported line associated with ‘fins out’ as longer

Question 28

Inattentional blindness - Moore and Egeth (1997) - implications

Answer 28

Even though participants were completely unaware of the fins, they influenced task performance

Attention may be needed for conscious perception

But perhaps you can unconsciously detect (and be influenced by) patterns in the world in the absence of attention

Question 29

summary

Answer 29

Attention needs to be able to effectively select important information from the environment.

• What might surprise you is how little you actually perceive outside of the information you are focusing on.
• This demonstrates attention as a capacity limited resource that needs to be selective.
• It also demonstrates the very important relationship between what we attend to and what we actually perceive.