Perception of Action

Question 1

What does Gibson’s ecological theory state?

Answer 1

Perception is designed so we can move and interact with our environment. Bottom-up in nature. Perception is unambiguous. Sensation IS perception. No learning required - forged by evolution.

Question 2

What research did Gibson do to develop his theory?

Answer 2

Worked with pilots in WW2.

Question 3

What is optic flow?

Answer 3

How objects appear as an observer moves past them. Helps us judge distance and speed. Self-produced - if you are stationary, you have no optic flow.

Question 4

What is gradient of flow?

Answer 4

How much of the scene is expanding on your retina gives you enough information to capture depth.

Question 5

What is focus of expansion?

Answer 5

A point in the distance where there is no optic flow, e.g the horizon.

Question 6

What are texture gradients?

Answer 6

How we use patterns of light to work out shape, distance, depth. We see larger and taller items as being closer to us.

Question 7

What is affordance?

Answer 7

The ability to discern possibilities for actions within the environment, and interactions with objects. elated to our own perception, and the context.

Question 8

What do changes in the optic array show us?

Answer 8

They contain important information about what kind of movement is taking place.

Question 9

What are the positives of the ecological theory?

Answer 9

High ecological validity.
Large number of applications: training pilots, road markings.
Good explanation for perception when viewing conditions are clear.
Highlights richness of perception in optic flow.
Provides an account for perception in animals and humans.

Question 10

What are the limitations of ecological theory?

Answer 10

Reductionist suggestion that perception occurs solely bottom-up.
Strong evidence shows that brain and long term memory influence perception.
Only supports the nature side of the nature-nurture debate.

Question 11

What did neo-Gibsonians such as David Lee find in their study with drivers?

Answer 11

Drivers use other information as well as optic flow. When driving straight, drivers do not look at the focus of expansion. When driving round a bend, they focus on a tangent point at the side of a road.

Question 12

What is time to contact theory?

Answer 12

We are constantly making calculations of the size and speed of expansion of objects moving towards us as this tells us the distance the object is from us.

Question 13

Explain the ecological approach to the time to contact theory?

Answer 13

TTC can be calculated using a single variable: size.

Question 14

What is tau?

Answer 14

The ability to work out the changing distance.

Question 15

What is motion parallax?

Answer 15

As you are moving, objects in the foreground are harder to focus on and seem to go by quicker than those in the background. This is because they take less time to pass your visual field.

Question 16

What are monocular depth cues?

Answer 16

Rely on information perceived from one eye, e.g size. Motion parallax uses monocular depth cues.

Question 17

What are binocular depth cues?

Answer 17

Information that is perceived by both eyes, e.g computing the distance to various objects.

Question 18

Explain Johansson’s study on biological motion detection.

Answer 18

Attached lights to actors joints. only the lights were visible in the dark. participants made accurate judgements about the actors’ movements and postures even though they could only see the lights - this shows humans are able to easily perceive motion and infer intentions from it.

Question 19

What does smoothness of movement in a person infer to other people?

Answer 19

The person is attractive, competent, trustworthy.

Question 20

Give some examples of what you can infer from how people move.

Answer 20

Mood, personality, purpose.

Question 21

What do mirror neurons do?

Answer 21

Fire when we watch motion, even if we are not moving. Link sensor perceptions with motor actions.

Question 22

Explain Calvino-Merino’s study on mirror neurons in different dancers.

Answer 22

Participants were experts in ballet or capoeira. Mirror neurons fired significantly more when the dancers were watching the dance they are experts in than the other dance. There was also a significant difference between expert dancers and non.

Question 23

What does the study on mirror neurons in dancers suggest?

Answer 23

There is an effect of our own movement experiences on how we perceive other’s movements.

Question 24

What is the impact on research into mirror neurons?

Answer 24

Help with rehabilitation of injured athletes or people whose motor skills are damaged by stroke.

Question 25

Environmental information is:

Answer 25

Dynamic. The rich visual information must be processed to safely negotiate a path for destination.

Question 26

What is the moving room paradigm?

Answer 26

When the walls move, adults sway but do not fall. Toddlers will fall.

Question 27

What does the moving room paradigm show?

Answer 27

Visual system overrides vestibular and proprioceptive. Active experience helps us tune the system. Optic flow helps keep your balance.

Question 28

What does the visual system do (in terms of movement)?

Answer 28

provides information about the surrounding environment, near and distant.

Question 29

What does the vestibular system do?

Answer 29

Assists with orientation, sensing changes in linear and angular speed with the directional pull of gravity.

Question 30

What is proprioceptive information?

Answer 30

Used to identify the position of body segments in relation to each other. is important for understanding of where we are in space.

Question 31

What is developmental coordination disorder?

Answer 31

An idiopathic movement disorder that affects 5-6% of children.

Question 32

Give some examples of how DCD affects movement.

Answer 32

children with DCD take smaller steps, spend more time with both feet on the ground than controls. They also incline their heads and trunk towards the ground which helps with their balance.