Exam 2- Lecture 5

Question 1

Driving and using cell phone

Answer 1

Four times higher risk of collision than when not being used
Because of limitations of attention
Texting while driving 6x more dangerous than drunk driving
98% say unsafe, 49% do it anyway

Question 2

Attention

Answer 2

Limited capacity to process information
-> competition between items for precessing (bottleneck/ capacity limits)

Attention is the mechanism that SELECTS the most important/ behaviorally relevant info at the COST of others
-> what is important changes depending upon goals of moment

Normally keeps the bias to processes info balanced, which involved a network of areas that integrate sensory and goal info (shown from spatial neglect)

Question 3

Two mechanisms of selection

Answer 3

Voluntary attention

• select info relevant to current goals and ignore irrelevant info (top-down)
• > ex. finding a friend wearing red in crowd

Reflexive attention

• re-orienting towards unexpected, but potentially important info (bottom-up)
• > ex. turning towards sound of sirens OR novel stimuli

NOT mutually exclusive

Question 4

Eye movements and visual attention

Answer 4

We can see details only at center of gaze

Make frequent eye movements to inspect objects of interest

• 3 per second
• called overt attention

Most eye movements are sudden jumps (saccades)
-each preceded by a covert shift of attention

Attention ALWAYS precedes eye-movements, but NOT all shifts of attention are followed by eye-movements
-> covert attention (without eye movement)

Question 5

Helmholtz’s visual attention experiment

Answer 5

Disassociation between attention and eye movement

Covert attention to specific region with no eye movements, but could not perceive others not from focused location

Question 6

Dichotic listening (Cherry, 1953)

Answer 6

Covert selection

Shadow and repeat info stream from one and ignore the other

Early selection

Question 7

Cocktail party effect

Answer 7

3 properties

1. Ability to select one info stream
2. Ability to covertly attend to another stream
3. Higher sensitivity to words of interest (e.g., one’s name)

Question 8

Summary

Answer 8

Limited capacity
- “bottlenack” in processing

Able to selectively attend to goal relevant info

• overtly (eye-movementss), but also covertly
  
  • > domain general (e.g., vision, audition)

Question 9

Johnsrude et al. (2013)

Tune out spouse

Answer 9

Can selectively listen to spouse’s voice and ignore others’

Can also filter out their voice

Question 10

Early selection

Answer 10

Most effective

-dichotic listening task

Question 11

Late selection

Answer 11

What goes to memory

What we act upon

Question 12

P1 (positive peak)

Answer 12

Early selection:
Larger for attended than unattended condition
Higher quality at attended location

Question 13

Is attentional selection early or late?

Answer 13

When does voluntary attention begin to affect info processing?

• > Early
• > Differences in auditory N1 and visual P1 due to attention begin well before 100 ms

Suggests incoming info is modulated as it arrives into sensory system
-> think: spotlight highlighting info

Question 14

Where in the brain does voluntary attention have an effect on processing?

Answer 14

Attention can modulate processing very early on, in LGN and V1 (high spatial specificity)
- Effectively deceases response time and increases amplitude of response

Question 15

Late selection

Answer 15

Stroop effect
Attentional blink
Flankers task (ignore letters on sides, focus on middle letter)

Question 16

Summary

Answer 16

Attention selectivity baises task-relevant info (to win competition against distracting noise) for perceptual processing, awareness, storage in memory, etc.

Attentional selection can be early on sensory inputs
Can also be late so that the to-be-ignored distractors compete for responses

Question 17

Feature integration theory

Answer 17

We perceive simple features (e.g., color) without focused attention, but we need attention to perceive objects defined by multiple features

Attention is used to INTEGRATE (“glue”) the FEATURES of an object

Preattentive stage

• visual input is decomposed into maps of simple features
• > separate for each color, orientation, etc.
• parallel, with NO capacity limitations
• only “pooled activity” from feature map is available to awareness (“approximately”)

Attentive stage

• attention is focused onto a location
• > features can be LOCALIZED and BOUND TOGETHER (conjoined)
  • > form object file (abstract representation of current features of object)
• serial (one location at a time)
• output is available to AWARENESS
• can DIRECTLY control behavior

Question 18

Feature search

Answer 18

Only look for specific feature (green rectangle)

Question 19

Conjuncture search

Answer 19

Look for specific target with more than one feature (vertical green rectangle)

Question 20

Linear function

Answer 20

Set size and reaction time

-TA trials twice as long as TP trials

Question 21

Spatial neglect

Answer 21

Ignore contralesional space
Sensory perception is INTACT
CAN direct voluntary attention to neglected side

Sensory-driven (reflexive) attention very impaired

Extinction
-problem only occurs when competition over visual fields

Question 22

Change blindness

Answer 22

Attention does not pick up change