Week 10

Question 1

What are the main functions of motion perception?

Answer 1

Breaking camouflage
Attracting attention
Segregating objects
Interpreting events/actions
Revealing structure from motion

Question 2

What is akinetopsia?

Answer 2

Condition where motion can’t be perceived due to brain damage

Question 3

When do we perceive motion?

Answer 3

Real motion: actual movement

Illusory motion: nothing moves (e.g., rotating snakes)

Apparent motion: illusion via discrete stimuli

Motion aftereffects: after viewing motion

Induced motion: background moves, so object appears to move

Question 4

What is motion-induced blindness?

Answer 4

Stationary objects disappear when surrounded by moving patterns

Question 5

What determines an object’s colour?

Answer 5

The wavelengths of light it reflects vs. absorbs

Question 6

What is the Trichromatic Theory of colour vision?

Answer 6

Colour vision based on 3 cone types:

S (blue)

M (green)

L (red)

Question 7

Which cones are missing in each type of colour deficiency?

Answer 7

Protanopia: L cones

Deuteranopia: M cones

Tritanopia: S cones

Question 8

What are the three opponent channels in colour vision?

Answer 8

Red-green
Blue-yellow
White-black

Question 9

What is the problem of colour constancy?

Answer 9

Object color depends on reflected light, which varies with lighting—but we still perceive stable colour

Question 10

How does the brain solve color constancy?

Answer 10

Habituation (to dominant scene colour)
Discounting the illuminant (comparing objects in scene)

Question 11

What did Heider & Simmel (1944) and point-light walkers both demonstrate?

Answer 11

Motion reveals actions and intentions

Question 12

What is the Footsteps Illusion (Anstis, 2003)?

Answer 12

High contrast objects seem to move faster than low contrast ones

Question 13

What is the Barber Pole Illusion?

Answer 13

Lines seen moving vertically due to terminators curving around edges of pole (e.g. barber pole)