Tetrachromacy Quiz
Questions: 16 · 10 minutes
1. A person can invent highly precise names for small differences among paint colors. Why is that not enough to demonstrate tetrachromacy?
Color naming is influenced by language, memory, attention, and training and does not establish an extra receptor channel
Functional tetrachromats cannot use ordinary color names
Paint colors stimulate rods but not cone cells
Only genetic testing can measure any form of color discrimination
2. How could random X-chromosome inactivation be relevant to proposed tetrachromacy?
It makes every retinal cell express all available opsin variants at once
It converts rod photoreceptors into an additional cone class
It may produce a retinal mosaic in which different cone cells express different X-linked opsin variants
It guarantees that the brain receives four independent color channels
3. What does “tetrachromacy” mean in color-vision science?
Color vision involving four functionally distinct classes of cone photoreceptor
Exceptional sensitivity from having a larger number of the usual three cone classes
The ability to name four basic categories of color consistently
Color perception produced by rods and all three usual cone classes working together
4. Which approach would provide the strongest evidence that someone uses an additional color channel?
Asking the person to describe a large set of paint samples
Using repeated, controlled psychophysical discrimination tasks with carefully specified spectral stimuli
Having the person sort gradients displayed on an uncalibrated phone
Sequencing opsin genes without testing visual performance
5. Which finding would be necessary for functional tetrachromacy rather than merely carrying an additional opsin variant?
A strong preference for subtle or muted colors
A family history containing different forms of color vision
The nervous system uses four distinct cone signals to make repeatable color discriminations
Four opsin-related gene variants identified in a DNA sample
6. A researcher wants to test whether a participant's unusual discrimination is repeatable rather than caused by guessing or stray cues. Which design is best?
Let the participant choose favorite colors from one printed chart
Use many randomized forced-choice trials, controlled spectra, suitable comparison groups, and replication
Use one difficult comparison under ordinary room lighting and accept the first response
Reveal the purpose of each trial so the participant can focus on the expected difference
7. How many cone classes normally support daylight color vision in a typical human trichromat?
Two
Three
Four
Five
8. Two lights are adjusted to look identical to typical trichromats but are reliably distinguishable to a participant. Why could this matter in tetrachromacy research?
A fourth functional receptor signal might separate stimuli that are metamers for trichromatic vision
Any two physically different lights must look different to every observer with typical vision
The result shows that the participant has more rods than cones
The participant has demonstrated better color vocabulary rather than different discrimination
9. The same fabric looks different under daylight and a household lamp. What is the best explanation?
The fabric changes its surface pigments whenever the light source changes
Cone cells stop adapting when viewing familiar objects
This effect occurs only in people with a fourth cone class
Different illuminants have different spectral power distributions, changing the light reflected to the eyes
10. What are Ishihara-style pseudoisochromatic plates mainly designed to assess?
The number of color words a person can use
Differences between cone-based and rod-based night vision
Common red-green color-vision deficiencies
Whether a fourth cone signal reaches the visual cortex
11. What primarily distinguishes one cone class from another?
Its location in a specific quadrant of the retina
Its pattern of sensitivity across wavelengths of light
The color name assigned to it by the viewer
Its ability to function without signals from other retinal cells
12. Why has some human tetrachromacy research focused on people with two X chromosomes?
All cone photoreceptors are encoded exclusively on the X chromosome
Two X chromosomes automatically produce four cone classes
Rod-based night vision is determined only by the number of X chromosomes
Different X-linked L- or M-opsin variants could potentially contribute distinguishable cone sensitivities
13. Which statement best describes tetrachromatic color vision in several nonhuman animals, including many birds?
It can involve four cone classes with distinct spectral sensitivities, sometimes including sensitivity into the ultraviolet
It means the animal sees the same colors as humans but at greater distances
It relies on three cone classes plus rods acting as a permanent fourth daylight channel
It results from four color-processing regions rather than different photoreceptors
14. A genetic report finds two different variants of an X-linked cone-opsin gene. What is the most accurate conclusion?
The person necessarily has four independently useful color channels
The finding proves superior color naming but not color discrimination
The person must have a red-green color-vision deficiency
The variants may create biological potential, but they do not by themselves establish functional tetrachromacy
15. An online test shows several nearly identical color patches on a standard RGB monitor. Why can it not confirm tetrachromacy?
Online testing measures rods rather than cones
Tetrachromats would perceive every RGB patch as completely different
The monitor, calibration, lighting, and image encoding limit the spectral information reaching the viewer
Color vision can only be assessed with printed pigments
16. Someone earns an unusually high score once on an uncalibrated online color-gradient test. What is the soundest interpretation?
The score confirms functional tetrachromacy because ordinary trichromats cannot perform unusually well
The test primarily establishes whether the person has a red-green color-vision deficiency
The result proves the person carries four distinct cone-opsin genes
The result is not sufficient evidence because display output, viewing conditions, practice, and normal variation can affect performance