Deck 4: Seeing in Colour

Question 1

Long wavelengths usually appear:

A) Red
B) Green
C) Grey
D) Blue

Answer 1

A

Question 2

The amount of white mixed with a hue defines its:

A) Reflectance
B) Saturation
C) Lightness
D) Unique hue

Answer 2

B

Question 3

In additive colour mixing, a mixture of red and green lights appears to the normal observer:

A) Brown
B) Purple
C) Turquoise
D) Yellow

Answer 3

D

Question 4

In the CIE 1931 chromaticity diagram, a colour lying on a straight line joining two points on opposite sides of the perimeter can be formed by:

A) A mixture of any three colours in the lower region of the diagram
B) A mixture of the colours on the perimeter at the ends of the line
C) A mixture of the colours at the nearest corners of the diagram
D) None of these

Question 5

Rod absorbance peaks at:

A) 419 nm
B) 531 nm
C) 558 nm
D) 496 nm

Question 6

Deuteranopes lack:

A) M cones
B) L cones
C) S cones
D) M and L cones

Question 7

A woman with a defect on one X chromosome of the gene for M cones is married to a man with normal colour vision. Of their daughters, on average:

A) Half will have defective colour vision and half will have normal colour vision, but be carriers of the defective gene
B) All will be carriers
C) Half will be normal and half will be carriers
D) All will have defective colour vision

Question 8

L-M colour opponency originates in:

A) Midget retinal ganglion cells
B) Koniocellular LGN cells
C) Parasol retinal ganglion cells
D) L cones

Question 9

Experiments in which coloured targets are masked by colour noise suggest:

A) Colours on the cardinal axes are the best maskers
B) Colours on the cardinal axes have no special status as maskers
C) Targets composed of colours on the cardinal axes are easiest to identify
D) None of these

Question 10

Neurons in monkey inferior temporal cortex are tuned to:

A) Only colours on the cardinal axes of colour space
B) Opponent colours
C) One of a wide range of colours
D) All colours

Question 11

The impairment of motion perception at isoluminance probably occurs because:

A) Cone contrast is reduced
B) The motion processing system is driven mostly by a luminance input
C) The S cone system is sluggish
D) Visual acuity is reduced at isoluminance

Question 12

Colour assimilation probably occurs because:

A) Complementary colours attract each other
B) Eye movements smear out signals from neighbouring photoreceptors
C) Parvocellular ganglion cells are sluggish
D) Receptive fields which signal colour are larger than those which signal spatial detail

Question 13

Which of the following probably does not contribute to colour constancy?

A) Cone excitation ratios
B) Rod signals
C) Cone adaptation
D) Familiar hues

Question 14

Trichromatic vision evolved in humans via a duplication of:

A) Rods
B) S cones
C) L cones
D) M cones

Question 15

Animals with dichromatic vision are said to be able to discriminate about 10,000 different colours. How large is the set of colours thought to be discriminable by those with trichromatic vision?

A) 100,000
B) 20,000
C) 1 million
D) 5 million

Question 16

Gilchrist demonstrated that perceived lightness depends on a comparison of surfaces:

A) In adjacent regions in the retinal image
B) In the upper region of the visual field
C) In the lower region of the visual field
D) In the same depth plane

Question 17

Li and Gilchrist showed that the lightest region of the scene in perceived as white unless:

A) A darker region is larger
B) The lightest region is surrounded by dark grey
C) The surrounding regions are in a different depth plane
D) The display is viewed monocularly

Question 18

Adelson suggested that lightness is computed by the visual system:

A) After information from the two eyes is combined
B) After a full 3D representation of the scene has been made
C) From a comparison of local regions of the scene
D) None of these

Question 19

Participants in an experiment, asked to select which colour of packaging of condoms suggested that the contents were 'durable' rather than 'refined', tended to choose:

A) Red
B) Purple
C) Green
D) Blue

Question 20

The visible spectrum runs from about:

A) 370 to 700 nm
B) 500 to 800 nm
C) 200 to 600 nm
D) 420 to 730 nm

Question 21

In additive colour mixing, a mixture of blue and green lights appears to the normal observer:

A) Brown
B) Purple
C) Cyan
D) Yellow

Question 22

M cone absorbance peaks at about:

A) 500 nm
B) 650 nm
C) 370 nm
D) 531 nm

Question 23

Blue cone monochromats:

A) Have no colour discrimination
B) Have normal visual acuity
C) Have some colour discrimination at twilight
D) Have abnormal scotopic vision

Question 24

Hofer et al. found, from their high-resolution images of the human retina, that blue cone density was about:

A) 2%
B) 20%
C) 15%
D) 6%

Question 25

Webster and Mollon found that after adapting the red-green opponent channel:

A) The appearance of yellow was unaffected
B) Yellow stimuli now had a blue tinge
C) Greenish-blue stimuli had the appearance of their blue as well as their green component altered
D) Green stimuli had a blue tinge

Question 26

Kiper et al. found that cells in V2 which responded to colour:

A) Had peak sensitivities from all regions of colour space
B) Responded to no other stimulus feature
C) Had peak sensitivities on the cardinal axes
D) Were very broadly tuned to colour

Question 27

Colour assimilation is greater in displays which contain:

A) Larger elements
B) Smaller elements
C) Blues and yellows
D) Reds and greens

Question 28

Bramao et al. concluded that colour is important in object recognition especially when:

A) The participant is young
B) The object is unfamiliar
C) The object is small
D) The colour is diagnostic

Question 29

Define additive and subtractive colour mixing. What have they revealed about human colour vision?

Question 30

What are the types of colour-deficient vision, and how are they to be explained?

Question 31

What individual differences in colour vision have been identified within the normal population?

Question 32

How is colour represented in visual cortex?

Question 33

How do we perceive lightness?