Topic 6: Movement and Action

Question 1

Explain the ecological approach to perception

Answer 1

Focuses on specifying the information in the environment used for perception

Emphasis on the study of moving observers to determine how their movement results in perceptual information that both creates their
perception and guides further movement

Question 2

According to the ecological approach to perception, what causes you to perceive movement in stationary objects if you are moving?

Answer 2

Your movement relative to the objects

Question 3

Flow of stimuli in the environment that occurs when an observer moves relative to that environment

Answer 3

Optic flow

Question 4

Provides information about speed/how fast the observer is moving

Answer 4

Gradient of flow

Question 5

Where the observer will end up if course is not changed

Answer 5

Focus of expansion (FOE)

Question 6

What are the two important characteristics of optic flow?

Answer 6

Optic flow is more rapid near the observer, and is slower farther away

No flow at the destination toward which the observer is moving (white dot)

Question 7

Describe a procedure measuring Reacting to Information Created by Movement

Answer 7

Have observers judge, based on optic flow, where they would be heading
relative to a reference point.

Typically done using computer-generated displays that create illusions of
optic flow but can also get a sense from stationary images as well.

Question 8

The ability to stand up straight and keep balance depends on the interactions between…

Answer 8

Vestibular system, somatosensory system, visual system

Question 9

What do swinging room experiments demonstrate?

Answer 9

Vision can override other sources of
balance information provided by the inner ear and the receptors in the muscles & joints.

Question 10

What visual direction strategy do we typically employ?

Answer 10

keep our body oriented/pointed toward the target

Question 11

Awareness of our position in an environment
while we move

Answer 11

Spatial updating

Question 12

Ability to navigate short distances in the
complete absence of visual stimuli

Answer 12

Muscle movements = indication of speed
and direction

Success depends on combining these
muscle movements + memory for target
location

Question 13

Travel to distant destinations that aren’t
immediately visible.

Answer 13

Wayfinding

Question 14

What does wayfinding involve?

Answer 14

Perceiving objects in the environment

Remembering these objects and their relation to the overall scene/environment

Knowing when to turn, and in what direction

Question 15

Why are landmarks an important source of information for wayfinding?

Answer 15

Objects on a route that can serve as cues to indicate where to turn

Question 16

Typical maze tasks contain…

Answer 16

Decision-point landmarks: objects at corners where a decision needs to be made to turn or not

Non-decision-point landmarks: objects that provide no critical information for navigation

Question 17

What is the relationship between memory and landmarks?

Answer 17

Individuals spend more time looking at decision-point landmarks and are more likely to
remember them.

Question 18

How did early research begin to conceptualize cognitive maps?

Answer 18

Studied how rats learned to run through mazes to find rewards

Question 19

Where are place cells found in humans?

Answer 19

Entorhinal cortex

Question 20

Groups of neurons that fire when in a specific spot, and only in that spot

Answer 20

Place cells

Question 21

Information about how an object can be used

Answer 21

Affordances

Question 22

Major brain region in the dorsal stream
for reaching and grasping objects

Answer 22

Parietal reach region

Question 23

Describe the size-weight illusion

Answer 23

Erroneously predicting weight when
perceiving two differently sized objects
that have the same weight.

Error occurs because we tend to
predict that objects we perceive as
being bigger = more force to lift

Question 24

What are the implications of research showing that when you deliver and perceive a hit to an object, the force of your grip increases exactly when the hit is delivered

Answer 24

Motor system correctly predicts the timing and force.

Question 25

Typically, we perceive motion when either…

Answer 25

1. An image moves across our retina.
2. We move our eyes to follow something that is moving in our field of view.

Question 26

the real, physical movement of a stimulus

Answer 26

Real motion

Question 27

The perception of motion of stimuli that aren’t moving

Answer 27

illusory motion

Question 28

What are the three types of illusory motion?

Answer 28

Apparent motion
Induced motion
Motion aftereffects

Question 29

Occurs when the motion of one object causes a nearby stationary object to appear to move.

Answer 29

Induced motion

Question 30

Occurs when viewing a moving stimulus causes a stationary stimulus to then appear to move

Answer 30

Motion aftereffects

Question 31

When Jack walks from left to right and you
move your eyes to follow him, portions of
the environment become covered as he
walks by them, and then uncovered when
he moves on. What does this create?

Answer 31

A local disturbance in the optic array

Question 32

Indicates that it is the observer who is moving
(either moving their eyes or entire body), and
not an object in the environment.

Answer 32

Global optic flow

Question 33

What are the three signals associated with corollary discharge theory?

Answer 33

1. A motor signal (MS): Indicates you have moved your eyes.
2. An image displacement signal (IDS): indicates an image has moved on the retina.
3. A copy of motor signal (CDS – corollary discharge signal)

Question 34

According to corollary discharge theory, movement is perceived when…

Answer 34

Comparator receives one, and only one,
of either the CDS or the IDS

Question 35

Accoridng to corollary discharge theory, if the comparator receives both signals…

Answer 35

No movement is perceived

Question 36

Which brain areas are associated with the “comparator” (Corollary discharge theory)?

Answer 36

V1 is important for preliminary
processing, motion perception is also a
function of activity in the middle temporal
area (MT) -Previously referred to as V5

Question 37

In extreme cases of bilateral damage to the middle temporal lobe, you can get…

Answer 37

Akinetopsia (lose the ability to perceive visual motion)

Question 38

Receptive fields in the MT are…

Answer 38

Directionally selective

Question 39

Occurs when only a portion of a moving stimulus is seen, as though viewed through a narrow aperture or in the view of a single neuron’s receptive field

Answer 39

Aperture problem

Question 40

What is the solution to the aperture problem?

Answer 40

Visual system pools the responses from several MT neurons at once to get a “truer” picture of how something is moving