wk2: ND - Visual Attention

Question 1

Define inattentional blindness

Answer 1

an individual fails to perceive an unexpected stimulus in plain sight

Question 2

Define attentional blink

Answer 2

is the phenomenon that the second of two targets cannot be detected or identified when it appears close in time to the first.

Question 3

How long of a duration should be between the presentation of 2 targets in sequence for us to perceive both?

Answer 3

at least 500ms between the two targets (this way we can counter the attentional blink)

Question 4

What are the two different ways attention can be classified?

Answer 4

Endogenous vs Exogenous
Spatial vs Feature-based

Question 5

Describe Exogenous attention

Answer 5

Exogenous: bottom up, (pre-attentive), feature search … effortless … leads to “pop out” [For example spotting a red balloon in a sea of blue balloons)

Question 6

Describe Endogenous attention

Answer 6

Top down … requires effort and takes time and depends on task and clutter (e.g. finding Wally. That’s right Americans it’s Wally not Waldo)

Question 7

What does endogenous vs exogenous attention relate to?

Answer 7

related to what drives the attention process

Question 8

What does spatial vs feature based attention relate to?

Answer 8

related to attentional bottleneck and its limited capacity for processing

Question 9

Describe spatial attention

Answer 9

helps to confine processing to a particular location/object (e.g. focusing on the road while driving)

Question 10

Describe feature-based attention

Answer 10

helps to process all objects sharing a common feature (e.g. all red cars in a car park)

Question 11

Describe parallel vs serial search

Answer 11

In broad terms, serial search assumes that items in a search display are attended to one by one and each examined as to whether it constitutes the target. In parallel search, all items are examined in parallel as to whether they are the target

Question 12

How do serial and parallel searches differ in their relation to attention? (2)

Answer 12

Parallel search: pre-attentive (pop out)
Serial search: deploys attention (takes time)

Question 13

What is Treisman’s feature integration theory? (that he developed after experimenting with visual search)

Answer 13

Postulates an attentional spotlight (‘covert attention’) acting on a visual area or areas early along the visual pathway that aids in early selection of visual field location for further processing.

Question 14

Where is the most likely source of the “attentional spotlight” postulated by Treisman?

Answer 14

Posterior parietal cortex

Question 15

How do the dorsal and ventral pathways interact?

Answer 15

There is a neural substrate for dorsal areas to gate what goes into the ventral area

Question 16

How do receptive field sizes change as we go along the ventral stream?

Answer 16

They get progressively larger. Presents problems relatign to position invariance or something

Question 17

What is the “Binding problem” in perception

Answer 17

If different stimulus attributes are processed in different cortical areas, how then do we correctly combine the features of one object?

Question 18

What solutions are there to the Binding problem? (2)

Answer 18

1. Treisman’s feature integration theory provides a solution: spotlight of attention acting on early visual area aids in selection of a VF location for further processing. Thus, binding errors do happen in posterior parietal cortical lesions
   2.. Another sol. = synchronisation b/w neurones that code for features that belong to the same object

Question 19

List 7 conditions where visual attentional mechanisms may be impaired

Answer 19

Hemispatial neglect
Developmental dyslexia
Acquired dyslexia
ADHD
Schizophrenia
Accidents (in traffic, using heavy machinery, etc.)
Sleep disorders

Question 20

Provide 3 examples for how selectivity of attention can be demonstrated

Answer 20

Inattentional blindness
Change blindness
Attentional blink