Attention

Question 1

What is attention?

Answer 1

Given limited capacity to process competing options, attentional mechanisms select, modulate, and sustain focus on information most relevant for behavior

Question 2

Attention sources

Answer 2

1. Exogenous: in the environment, reflexive, automatic, “bottom-up”
2. Endogenous: in the mind, voluntary, intentional, “top-down”

Question 3

Attention targets

Answer 3

1. External: sensory info, in the environment
   
   • A sensory modality, spatial location, feature, or object
2. Internal: mental representations, in the mind
   
   • A memory, imagery, or plan

Question 4

Attention types

Answer 4

1. Overt and covert
2. Transient and sustained
3. Selective and divided

Question 5

Overt vs. Covert

Answer 5

• Overt: Involves actual movement of the sensory surface, e.g.: moving
  the eyes, directing the ear
• Covert: Does not involve actual movement, e.g.: “looking out the corner
  of your eye”, “eavesdropping on a conversation at the next table”

Question 6

transient vs. sustained

Answer 6

• Transient: Momentary focus on something
• Sustained: Prolonged focus on something

Question 7

Selective vs. divided

Answer 7

• Selective: Focus on one thing to the exclusion of others
• Divided: Try to focus on multiple things simultaneously

Question 8

Dichotic listening

Answer 8

-Source: endogenous
● “Attend to the left ear”
- Target: external
● Sounds entering ear
- Covert
- Sustained
- Selective

Question 9

Dichotic listening: Cherry (1953)

Answer 9

• Could report existence of
  message
• Could report gender of
  speaker
• Could NOT report content

Question 10

Dichotic listening: Moray (1959)

Answer 10

• Could report change in
  gender of speaker
• Could report change in
  pitch of a tone
• Could NOT report a word
  repeated 35 times!
• Could report hearing own
  name

Question 11

Dichotic listening: Gray & Weddeburn (1960)

Answer 11

• Told to shadow left ear
• Left ear hears: “Dear 7 Jane”
• Right ear hears: “9 Aunt 6”
• Participant reports: “Dear Aunt Jane”
• Meaning of unattended words
  being taken into account

Question 12

Dichotic listening: McKay (1973)

Answer 12

• Meaning of biasing word
  (“river” or “money”) in
  unattended ear affected
  participants’ choice
• However, participants were
  unaware of presentation of
  biasing words

Question 13

Attentional selection models

Answer 13

• Early all-or-none filtering (Broadbent) occurs between low-level perceptual and high-level semantic analysis
• Early attenuation (Treisman) occurs between low-level perceptual and high-level semantic analysis
• Late selection model (McKay) occurs between high-level semantic analysis and decision-making/memory storage
• Strategic control of attention:
  ● Early versus late selection can
  be chosen based on situation and approach
  ● Attention is applied by top-
  down modulation

Question 14

Electroencephalography (EEG)

Answer 14

• Non-invasive technique
• Measures surface electric fields generated by post- synaptic potentials in
  dendrites of neurons
• High temporal resolution: signal sampled >1000/sec
• Low spatial resolution: up to 256 electrodes

Question 15

Event-related potentials (ERPs)

Answer 15

• Average of EEG signals
• Time-locked to event of interest
• Typically plotted with negative up

Question 16

Attentional stream paradigm

Answer 16

• Random sequence of auditory “pips”
• Occasional deviant targets (different volume or pitch)
• Instructed to attend to one ear
• No effect of attention on brainstem evoked potentials
• Effect of attention on midlatency potentials (primary auditory) and late waves (secondary/tertiary auditory)

Question 17

Posner’s orienting task

Answer 17

• Maintain central fixation
• Spatially cued trials
  ● 80% valid
  ● 20% invalid
• Neutral trials
  ● No spatial cue
• Source: endogenous
• Target: external
• Covert
• Transient
• Selective?

Question 18

(McAdams and Maunsell, 1999)

Answer 18

• Orientation tuning curve: Attention causes gain (multiplicativescaling), but no change in feature selectivity

Question 19

Visual attention and V4 neurons

Answer 19

Attention enhances signal-to-noise ratio:
- No contrast:
● Small response
● Small change
- Subthreshold/Medium:
● Medium response
● Big change
- High contrast
● Big response
● Small change

Question 20

Synchronization in V1 and V4 (Bosman et al. 2005)

Answer 20

• Recording local field potentials (LFPs) in V1 & V4
• Attention to a stimulus increases synchronization between brain areas representing that stimulus

Question 21

The effects of attention

Answer 21

• Attention affects reaction time, accuracy, and awareness of sensory stimuli
• Attention can have effects less than 100 ms after stimulus onset
• Attention modulates neural activity in brain areas for locations and objects
• Attention enhances neural response to attended stimuli (e.g. enhanced signal-to-noise ratio)
• Attention increases neural synchronization between brain areas

Question 22

Unilateral (hemispatial) neglect

Answer 22

• A defict of attention
• A deficit in perceiving & responding to stimulation contralateral to damaged hemisphere
• Cannot be explained by primary sensory or motor disturbance

Question 23

Reference frames of of neglect

Answer 23

• Spatial
  ● e.g. neglect of left side of space
  ● Location-based attention
• Object-based
  ● e.g. neglect of left side of objects
  ● Object-based attention

Question 24

Attentional control network

Answer 24

Regions involved in endogenous and exogenous shifts of attention

Question 25

Role of frontal eye fields

Answer 25

FEF stimulation enhances V4 response, only when stimulus occurs in V4 receptive field

Question 26

Change blindness

Answer 26

changes in a picture or scene over time are not immediately apparent if not attended to

Question 27

Flicker paradigm (Resnick et al. 1997)

Answer 27

Image and one similar one with something missing or different flicker between each other
- endogenous, external, overt, transient, and selective