CH 5 Colour Perception (QUESTIONS)

Question 1

What 3 dimensions does the perception of colour rely on?

Answer 1

1. Hue ⇨ wavelength of light (green vs. blue)
2. Saturation ⇨ purity of light (red vs. pink)
3. Brightness ⇨ intensity of light (white vs. black)

Question 2

What were the two opposing dominant theories fore colour perception in the 19th century?

Answer 2

Trichromatic & Opposing-process theory

Question 3

What were 2 main concerns of the Opponent-process side with the Trichromatic theory?

Answer 3

1. When you asked people on the streets what the primary colours were they would name 4 (RGBY) not 3 (RBG)
2. Didn’t explain after-images

Question 4

How was the Trichromatic & Opposing-process theory dispute resolved?

Answer 4

Both theories were in fact, true.

• Evidence indicates 3 types of cone receptors as proposed by trichromatic theory, but also indicates opponent-process type cells at ganglion, thalamus and visual cortex levels
• Visual system wired such that output from the cone systems produced opponent-process responses

Question 5

Colour vision deficiencies (4)

Answer 5

1. Rod monochromats
2. Protanopia
3. Deuteranopia
4. Tritanopia

Question 6

While most visual information is received by the _____________, some projections are also sent to the _______________

Answer 6

• Primary Visual Cortex
• Superior colliculi in the midbrain

Question 7

The Primary Visual Cortex is arranged in _______/_______; Neurons in each _________ analyze information for a ________ _______ on the _______ (e.g., ________, __________, __________,________)

Answer 7

• Tiles/Modules
• Module
• Small Area
• Retina
• Colour, Shape, Orientation, Movement

Question 8

Neurons within the same _______ of the _______ have the same _______

Answer 8

• Tile
• Primary visual field
• Receptive field

Question 9

Organization of ganglion cells produces what type of receptive fields? Why is this important?

Answer 9

Centre-surround

• Important: Makes us sensitive to line and edge information

Question 10

Who identified cortical cells?

Answer 10

Hubel & Weisel

Question 11

What is visual processing characterized by? (2)

Answer 11

1. Bottom-up/data-driven processing
2. Hierarchal organization

Question 12

What conditions can damage on the second level parietal lobe cause? (2)

Answer 12

1. Motion Agnosia
2. Balint’s syndrome

Question 13

What conditions can damage on the second level temporal lobe cause? (2)

Answer 13

1. Visual agnosia
2. Prosopagnosia