Unit 4(C):
Vision
Mr. McCormick
A.P. Psychology
Do-Now
(Discussion)
 Raise your hand if you are either
nearsighted or farsighted.
 What causes Nearsightedness
(Myopia) and Farsightedness
(Hyperopia)?
Transduction
 Transduction:
 Conversion of one form of energy into another
 Transformation of stimulus energies, such as
sights, sounds, and smells into neural
impulses the brain can interpret
The Stimulus Input: Light Energy
Visible
Spectrum
The Stimulus Input: Light Energy
 Wavelength:
 The distance from the peak
of one light or sound wave
to the peak of the next
 Hue:
 Dimension of color that is
perceived
 Determined by the
wavelength of light
 E.g. green, blue
Wavelength (Hue)
Violet
Indigo
400 nm
Short wavelengths
Blue
Green
Yellow
Orange
Red
700 nm
Long wavelengths
Different wavelengths of light result
in different colors.
The Stimulus Input: Light Energy
 Intensity:
 The amount of energy in a light or sound wave
 Determined by the wave’s amplitude
 E.g. brightness (vision), loudness (hearing)
Intensity (Brightness)
Blue color with varying levels of intensity.
As intensity increases or decreases, blue color
looks more “washed out” or “darkened.”
Accommodation
 Accommodation:
 The process by which the eye’s lens changes shape to focus
near or far objects on the retina
The Eye
The Retina
Receptors in the Human Eye
Demonstration: Rods and Cones
 When looking at
something through your
peripheral vision,
why is it difficult to
determine its color?
The Optic Nerve,
Blind Spot, and Fovea
Demonstration:
Test Your Blind Spot
 Directions:
 Looking at your sheet, close your left eye, and fixate your right
eye on the black dot. Move the page towards your eye and away
from your eye. At some point the car on the right will disappear
due to a blind spot.
Visual Information Processing
Parallel Processing
From Sensation to Recognition
Young-Helmholtz Trichromatic Theory
and Color Blindness
Color Blindness is a genetic disorder,
in which people are blind to green or red colors.
This supports the Trichromatic Theory.
Ishihara Test
Opponent-Process Theory
Opponent-Process Theory
Review
 When looking at an object, what determines the
color and brightness that we perceive?
 Discuss the path in which light travels between
entering the eye and reaching the brain.
 What is parallel processing?
 Differentiate between the Young-Helmholtz
Trichromatic Theory and the OpponentProcess Theory of vision.
Homework
 Research Study Response #5: “Take a
Long Look” (Pgs. 36-42)
 Unit 4 FRQ
 Unit 4 Quiz: “Sensation and Perception”
 (W) 11/16/11