lecture 6: color vision

What is the Principle of Univariance in color perception?

It states that any stimulus evokes a response whose strength is determined by both intensity and wavelength, leading to indistinguishable stimuli despite variations.

What are the two receptor systems involved in color vision according to the lecture?

1) A primordial dichromatic system (blue/yellow) seen in most mammals, and 2) A second system (red/green) evolved in old-world primates.

What are the three types of color blindness mentioned in the lecture?

Protanopes (lack long wavelength cone), Deutranopes (lack medium wavelength cone), and Tritanopes (lack short wavelength cone).

What theory explains how any single wavelength can be matched by a mixture of three other wavelengths?

Trichromacy theory.

How does color constancy affect our perception of colors under different lighting conditions?

It allows us to perceive colors consistently despite significant changes in the illuminant, as illustrated by the color perception of 'the dress'.

What is the role of the opponent processes in color vision?

They compare signals from different types of cones (blue/yellow and red/green), facilitating color discrimination through spatially antagonistic pathways.

What does color mixing by addition involve?

For 'normal' observers, any single wavelength can be matched perfectly by a mixture of three other wavelengths, highlighting the physiological aspect rather than a strict primary color physics.

What is the phenomenon observed in color blindness simulations for normal vision?

Normal vision shows clear differentiation in colors, while color blindness simulations (like Protanopia and Deuteranopia) exhibit altered perceptions of red, green, and yellow.

What are the physiological components involved in human color perception based on the lecture?

The retinal ganglion cells, various types of cones, and processes in the visual cortex that contribute to color perception.

Why do evolutionary theories suggest that humans have three types of cones?

It enables a more complex color vision system to aid in foraging for fruits and foliage, improving survival and adaptability.