Lecture 12

Question 1

Describe action based accounts of perception

Answer 1

the purpose of perception is to create a representation in the mind of how one can interact
with their environment

Question 2

Describe the action-specific perception hypothesis

Answer 2

that one’s environment is perceived in
terms of how they are able to act on it

Question 3

What is a rule about attentional capture

Answer 3

motion attracts attention

Question 4

Describe event boundaries and motion

Answer 4

• Motion is also a cue that we rely on for distinguishing between event
  boundaries
• e.g. changes in speed/acceleration of actor’s hands was a good predictor
  of subjective judgments about events (Zacks et al. 2009)

Question 5

What is akinetopsia?

Answer 5

an inability to perceive motion

Question 6

What is real motion?

Answer 6

when an object is physically moving

Question 7

What is apparent movement?

Answer 7

stationary
stimuli are presented in slightly different locations

Question 8

Describe induced motion

Answer 8

movement of one object (usually a larger object, e.g.
clouds) results in the perception of movement in another object (usually a
smaller object, e.g. the moon)

Question 9

Describe motion aftereffect

Answer 9

Observer looks at movement of object for 30 to 60 seconds,
then a stationary object, and movement appears to occur in opposite direction from
original movement

Question 10

What is an example of motion aftereffect

Answer 10

Waterfall illusion

Question 11

Describe Larsen study

Answer 11

• Control condition: two squares in slightly different positions are briefly
  presented simultaneously
• Real motion condition: a small square is moved back and forth
• Apparent motion condition: two squares are quickly alternated on alternate
  sides of the display so as to create illusory motion

Question 12

What is the ecological approach?

Answer 12

what/how information directly
available in the environment is useful to guide perception/action

Question 13

What is the optic array?

Answer 13

the structure created by surfaces, textures, and contours in
the environment, which change as the observer moves through space

Question 14

What are the 2 things that can influence the optic array?

Answer 14

1. Local disturbances in the optic array: Objects moving relative to background (e.g. such
   that portions of stimuli are periodically covered and uncovered, e.g. the background and
   objects)
2. Global optic flow: Overall movement of the entire optic array (as a complete whole, i.e.
   without any local disturbances)

Question 15

When did Gibson think we perceived motion?

Answer 15

one part of the visual scene moves relative to the
rest of the scene

Question 16

When did Gibson think we didn’t perceive motion?

Answer 16

the entire field moves, or remains stationary

Question 17

What is corollary discharge theory?

Answer 17

hypothesizes that movement perception depends on
three signals:
- image displacement signal
-motor signal
- corollary discharge signal

Question 18

What is the image displacement signal?

Answer 18

movement of image stimulating receptors
across the retina

Question 19

What is the motor signal?

Answer 19

signal sent to eyes to move eye muscles

Question 20

What is the corollary discharge signal?

Answer 20

derived from the motor signal (essentially a
‘carbon copy’ of whatever the motor signal is doing, though it gets sent to a
different part of the brain for another purpose)

Question 21

Describe real movement neurons

Answer 21

• Real-movement neurons found in monkeys:
• Respond when a stimulus moves
• Do not respond when eyes move