03_Sensation and Perception Flashcards
Two theories of color vision
Trichromatic theory (Young-Helmholtz)
Opponent-Process Theory (Hering)
Trichromatic theory
Three types of color receptors (cones)
Each are receptive to a different primary color
All colors are produced by variations in cone activity
Opponent-Process Theory
Three types of bipolar receptors:
Red-green
Yellow-blue
White-black
Colorblindness: cause
Genetic defect that affects one or more of the three types of cones
Usually X chromosome
Parents of female with color blindness
Trait must be inherited from both parents
Parents of male with color blindness
Can be inherited only from mother alone
Depth perception:
Retinal Disparity
The closer an object, the greater the disparity of the two images
The Four Cutaneous Senses
Pressure/touch
Warmth
Cold
Pain
Dermatomes
Axons that carry information from cutaneous receptors to spinal cord through dorsal roots
Gate-Control Theory Of Pain
CNS can only process a limited amount of sensory information at any one time
Cells in the spinal cord block incoming pain signals
Synesthesia
“Joining senses”
Stimulation of one sensory modality triggers a sensation in another sensory modality
Unknown cause
Involuntary, due to biological factors
Psychophysics
Study of the relationship between physical stimulus magnitudes and corresponding psychological sensations
Three Psychophysical Laws
Weber’s Law
Fechner’s Law
Steven’s Power Law
Weber’s Law
The more intense the stimulus, the greater the increase in intensity required for a Just Noticeable Difference
e.g. 1 gram added to 10 grams, 10 grams added to 100
Fechner’s Law
Logarithmic Extension of Weber’s law
Experience of stimulus intensity increases arithmetically as stimulus intensity increases geometrically
