Electromagnetic vs' Visible Light Spectrum

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Electromagnetic vs. Visible Light Spectrum (350
nm 700 nm)
Wavelength in nanometers (nm) (nanometer 1
millionth of a millimeter)
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THE STIMULUS
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THE VISUAL APPARATUS
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RODS and CONES
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COLOR VISION THEORY
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Subtractive and Additive Mixtures
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SUMMARY OF COLOR THEORY
TRICHROMATIC T. O.P. Theory are complementary
TRICHROMATIC T. explains retinal (CONE) processing
O.P. Theory explains post-retinal processing
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HEARING

• How can we tell different sounds apart?

• How can we locate sounds in space?

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THE EAR
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Place Theory of Pitch Perception
1928 discovery of the mechanical characteristics
of neural transduction in the inner ear.
Georg von Bekesy 1899 - 1972
Depending upon the frequency of the sound, the
traveling waves achieved maximum amplitude in
different locations
Nobel Prize 1961
Good explanatory power for hi (20K Hz)
frequencies down to 500 Hz
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Frequency Theory of Pitch Perception
Hair cells of the ear (Basilar membrane) mimics
the sound by firing at a rate that is equal
to/related to the frequency of the sound
Hermann von Helmholtz 1821 - 1894
Good explanatory power for low (20 Hz)
frequencies up to 5000 Hz - Volley principle for
1,000 5,000 Hz