13: Sensation & Perception: Visual attraction

Question 1

Attention is the ability to …

Answer 1

preferentially process some parts of a scene/stimulus @ the expense of processing other parts of the scene/stimulus

Question 2

why is attention needed

Answer 2

1. your perceptual system has a limited capacity
   - you can’t process everything in the visual scene simultaneously
   - attention helps us avoid being overwhelmed

Question 3

Overt attention involves …

Answer 3

looking DIRECTLY AT an object

Question 4

Covert attention involves …

Answer 4

looking AT 1 object but ATTENDING TO ANOTHER object

Question 5

eye movements b/w fixations are ___

Answer 5

ballistic (very fast)

Question 6

ballistic eye movements are “___”

Answer 6

saccades

Question 7

when a person looks @ an object, they are said to ____ it

Answer 7

fixate

Question 8

saccades are:

Answer 8

jumps of eye movement from object to object

Question 9

fixations are:

Answer 9

rest b/w saccades/jumps where the eye stays looking directly @ 1 part of the scene

Question 10

desc the phenomenon “attentional capture”

Answer 10

• involuntary
• when a scene is 1st presented, fixations are captured by SALIENT parts of it
• salient = noticeable parts

Question 11

what are the 2 processes (IN ORDER) that direct our attention & briefly desc them

Answer 11

1. initial involuntary process (mediated by attentional capture)
2. subsequent voluntary process (guided by GOALS & ur EXPECTATIONS)

Question 12

what captures our attention?

Answer 12

contrast:
- size
- colour
- orientation
- motion/flickering

Question 13

saliency maps determine ____ you ____ fixate

Answer 13

WHERE you INITIALLY fixate

Question 14

why do your expectations determine fixations?

Answer 14

cause if an object is unexpected, you will fixate on it for longer & fixate it more often
- contradict anticipated ideas abt scene

Question 15

tend to fixate on objects that are _____ inconsistent or ____ inconsistent w/ a scene

Answer 15

1. semantically
2. syntactically

Question 16

what are the effects of attention? (3)

Answer 16

1. speeds responses
2. influence appearance
3. influence physiological responding

Question 17

desc experiment where attention caused a change in appearance of object

Answer 17

• Carrasco et al (2004)
• peripheral cue caused participants to desc 1 circle as greater in contrast even if BOTH were the SAME

Question 18

what directs our attention?

Answer 18

• where you fixate
• fixations initially INVOLUNTARY & det by saliency of scene
• THEN, they’re VOLUNTARY: goal directed, influenced by expectations

Question 19

desc the binding problem

Answer 19

issue of how an object’s individual features are combined to create a coherent perception

Question 20

why does the binding problem arise?

Answer 20

because diff aspects of a stimulus are processed INDEPENDENTLY (often in diff brain areas)

Question 21

what does Feature Integration Theory (FIT) suggest?

Answer 21

binding problem is solved by attending to ONLY 1 location AT A TIME
- only features w/ THAT location are processed, so only those features are BOUND (helps avoid illusory conjunctions)

Question 22

what are illusory conjunctions

Answer 22

incorrect bindings
- letters & colours recalled correctly but bound wrongly

Question 23

what is a prediction of FIT?

Answer 23

that if attention is inhibited, illusory conjunctions of objects’ features occur

Question 24

why was RM prone to illusory conjunctions?

Answer 24

• cause of Balint’s syndrome
• couldn’t focus attention on a SINGLE object @ a time

Question 25

desc conjunction search

Answer 25

if the target object differs from the distractors only by its particular conjunction of features

Question 26

conjunction searches are ___ (pace)

Answer 26

SLOW

Question 27

why are conjunction searches slow?

Answer 27

because you need to attend to EACH OBJECT @ a time before you can determine if its the target

Question 28

feature searches are ___ (pace)

Answer 28

fast

Question 29

why are feature searches fast?

Answer 29

because binding doesn't need to occur, attention does not have to be placed on each item to find the target

Question 30

desc feature search

Answer 30

when the target object contains a feature that the distractors DON'T HAVE

Question 31

____ searches require the binding problem to be solved

Answer 31

CONJUNCTION

Question 32

____ searches DON'T require the binding problem to be solved

Answer 32

FEATURE

Question 33

desc change blindness

Answer 33

unable to notice change in scene because: 1. you can only remember a few parts of the scene @ a time 2. if you don't attend to a part, you won't remember it

Question 34

why doesn't change blindness occur all the time?

Answer 34

cause changes usually prod MOTION TRANSIENTS - draws attention to the location change, making it easy to spot the change

Question 35

how to prevent motion transient?

Answer 35

have a blank screen b/w 2 images, jumbles features of the scene making it hard to notice the change