W3 - Colour Flashcards
Why do people perceive different colors in #TheDress illusion?
overexposure, Different viewing conditions,Forced-choice responses influencing color naming, Individual differences in color processing and past experiences. The failure of color constancy
How does overexposure affect the perceived colors of the dress?
Overexposure changes the measured colors in the photograph compared to the real dress.
What experimental findings support the role of viewing conditions in #TheDress illusion?
Under controlled laboratory conditions (Lafer-Sousa, 2015): 53% of participants saw the dress as blue and black. And 40% saw it as white and gold. - This suggests that perception is influenced by individual differences beyond just external viewing conditions.
Why is the dress debate not just about naming colors?
Research (Gegenfurtner et al., 2015) showed: Naïve observers gave consistent answers when asked openly, rather than in a forced-choice format. “White-gold” perceivers matched the dress with light blue and brown rather than actual white and gold. This indicates true perceptual differences rather than just differences in naming colors.
What determines our conscious experience of color?
It depends on cells in the eye that are sensitive to particular wavelengths of light within the visible spectrum, which is part of the electromagnetic spectrum.
What are the two types of photoreceptor cells in the retina?
- Rods – Night vision, no color perception. 2. Cones – Daylight vision, color perception.
What are the three types of cones and their corresponding colors?
- S-cones – Blue, 2. M-cones – Green, 3. L-cones – Red
How does color information travel from the retina to the brain?
Retina to Lateral Geniculate Nucleus (LGN) to Visual Cortex (V1-V8)
What is the role of the visual cortex in color processing?
V1 & V2 (&V3): Initial color and spatial vision processing. V4 & V8: Conscious color perception and color constancy.
What is the visible spectrum, and how does it differ among species?
The visible spectrum is the range of light wavelengths human eyes detect. Most mammals are dichromats (2 cone types). Humans and some primates are trichromats (3 cone types). Some animals (e.g., birds, insects, snakes) can see ultraviolet or infrared light.
What are the dorsal and ventral streams in vision?
Dorsal (“Where”) Stream – Processes motion, depth, and action. Ventral (“What”) Stream – Recognizes objects and colors.
How common is color blindness in the population?
Around 8% of men and 0.4% of women are colorblind.
What causes color blindness?
A missing or defective cone type in the retina.
What is protanopia?
A lack of red cones. - Prevalence: Men: 1%, Women: 0.01%.
What is protanomaly?
A miss-tuned red cone (responds to the wrong wavelengths). - Prevalence: Men: 1%, Women: 0.03%.
What is deuteranopia?
A lack of green cones. - Prevalence: Men: 1%, Women: 0.01%.
What is deuteranomaly?
A miss-tuned green cone (responds incorrectly to light). - Prevalence: Men: 5%, Women: 0.35%.
What is tritanopia?
A lack of blue cones (extremely rare). - Prevalence: Men & Women: <0.01%.
What is rod monochromacy?
A condition where no cones are present—only rods, leading to total color blindness.
What is cone monochromacy?
A condition where only one cone type is present, making color vision very limited.
What is tetrachromacy, and who has it?
Some women have four cone types instead of three, allowing them to see more color variations than the average person.
What is cerebral achromatopsia, and what causes it?
It is cortical color blindness due to damage to V8, leading to loss of color perception despite functional photoreceptors. - can detect brightness but not colour
What is color opponency?
The visual system processes colors in opposing pairs: Red-Green Opponency and Blue-Yellow Opponency
How does the brain calculate color perception?
The visual system compares ratios of colors (e.g., how much red vs. green), creating signals that define color perception.
