PSYCH 1100H Lecture Notes - Lecture 1: Parallax, Binocular Disparity, Near-Sightedness
5 Oct 2018
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Sensation & Perception
Part 2
Ch. 5 Pages 147-172
Color Vision
Trichromatic theory: the existence of different types of cones for the detection of short,
medium, and long wavelengths
• All other colors = combinations of these three wavelengths.
• Vision uses 3 colors:
o Blue (short)
o Green (medium)
o Red (long)
Trichromatic Theory of Color Vision
Perception of color is based on the response rates of three kinds of cones
Opponent Process Theory
Opponent process theory: we have a red-green color channel and a blue-yellow color channel
in which activation of one color in each pair inhibits the other color
• Red / Green
• Yellow / Blue
Color afterimage
• pairs of visual neurons that work in opposition
Color blindness: inability to distinguish two or more shades
Gestalt Principles
We are born with a number of built-in tendencies to organize incoming sensory information in
certain ways
• This simplifies the problem of recognizing objects
Figure-ground: we visually pull the figure part of the stimulus forward while visually pushing
backward the background
• Reversible figure/ground relationship
Similarity: similar stimuli are grouped together
Proximity: objects that are close together tend to be grouped together
Continuity: we assume that points that form smooth lines when connected probably belong
together.
Closure: the tendency to complete a figure
Simplicity: we will use the simplest solution to a perceptual problem
Document Summary
Trichromatic theory: the existence of different types of cones for the detection of short, medium, and long wavelengths: all other colors = combinations of these three wavelengths, vision uses 3 colors, blue (short, green (medium, red (long) Perception of color is based on the response rates of three kinds of cones. Opponent process theory: we have a red-green color channel and a blue-yellow color channel in which activation of one color in each pair inhibits the other color: red / green, yellow / blue. Color afterimage: pairs of visual neurons that work in opposition. Color blindness: inability to distinguish two or more shades. We are born with a number of built-in tendencies to organize incoming sensory information in certain ways: this simplifies the problem of recognizing objects. Figure-ground: we visually pull the figure part of the stimulus forward while visually pushing backward the background: reversible figure/ground relationship. Proximity: objects that are close together tend to be grouped together.
