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Transduction. How is this important when studying sensation?. Stimulus energies to neural impulses. For example: Light energy to vision. Chemical energy to smell and taste. Sound waves to sound. Conversion of one form of energy to another. Vision. We only use light energy to see.
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Transduction How is this important when studying sensation? Stimulus energies to neural impulses. For example: Light energy to vision. Chemical energy to smell and taste. Sound waves to sound. Conversion of one form of energy to another.
Wavelength • The distance from the peak of one light wave to the peak of the next. • The distance determines the hue (color) of the light we perceive.
Intensity The amount of energy in a light wave. Determined by the height of the wave. The higher the wave the more intense the light is.
Feature Detection The concept that specific nerve cells in the brain respond to specific features of the stimulus, such as shape angle or movement.
Parallel Processing • The processing of several aspects of a problem simultaneously. Motion Form Color Depth
How do we see in color? What color is this dragon?
Color • The dragon is anything but red. • The dragon rejects the long wavelengths of light that to us are red- so red is reflected of and we see it. • Also, light has no real color. • It is our mind that perceives the color.
Young-Helmholtz Trichromatic (three color) Theory • Realized that any color can be created by combining the light waves of three primary color- RED GREEN BLUE • So they guessed that we have 3 different types of receptor cells in our eyes. Together they can pick any combination of our 7 million color variations. • Most colorblind people simply lack cone receptor cells for one or more of these primary colors.
Opponent-Process Theory • We cannot see certain colors together in combination (red-green, blue-yellow, and white-black). These are antagonist/ opponent colors. Tube and marble example.
Hearing Aka: Audition
Frequency the number of complete wavelengths that pass through point at a given time. This determines the pitch of a sound.
Amplitudeis how loud the sound is. The higher the crest of the wave is the louder the sound is. It is measured in decibels.
How do we perceive differences in pitch? There are two theories……..
Helmholtz’s Place Theory • We hear different pitches because different sound waves trigger activity at different places along the cochlea’s basilar membrane.
Frequency Theory • We sense pitch by the basilar membrane vibrating at the same rate as the sound. • But this theory has trouble explaining high pitch sounds because our hairs cannot vibrate at certain speeds. • This problem can be explained using the volley principle.
Hearing loss • Conduction Hearing Loss: caused by damage to mechanical system of ear. • Sensorinueral hearing loss: caused by damage to cochlea’s receptor cells or to auditory nerves.
Was I born to love peanut butter & jelly? What is the bigger question here? Nature versus Nurture
Why do we study smell and taste together? • SENSORY INTERACTION: the principle that one sense may influence another.
So….Was I born to love peanut butter & jelly? Lets take a look at the Nature perspective first.
How do we taste? • Taste (and smell) are chemical senses. What is the central muscle involved in taste?
Papillae • Those bumps on our tongue are called Papillae. • Papillae help grip food while your teeth are chewing. They also have another special job - they contain your taste buds
Taste Buds Map out the tongue
But what about smell? Can our sense of smell be biologically based?
Gender related odors • Can you smell the difference between?
So can we smell the difference? • Well….yes and no. Pheromones • Chemical messengers that are picked up through our sense of smell. • Founded in the early 1930’s by studying silkworms. • Jury is still out on whether they exist in humans. Best evidence we have comes out of the university of Chicago.
