Sensation and Perception

Sensation- Stimulation of sense organs
1. Absorption of energy (light/sound waves), by sensory organs such as our eyes and ears
Perception- selection, organization, and interpretation of sensory input
1. Organizing and translating sensory input into something meaningful
  1. Ventral stream in the brain associated with our perception of the world
  2. Dorsal stream in the brain associated with action and control of goal directed movements
Visual System
1. In order to see, we must have light. Light waves vary in amplitude and wavelength.
  1. Amplitude- affects perception of brightness
  2. Wavelength- affects perception of colour
2. The Lens of the eye
  1. Transparent structure that focuses light rays onto the retina
    1. The retina absorbs light, processes images, and sends visual information to the brain
      1. Rods
        Play a key role in night vision and peripheral vision
      2. Cones
        Play a key role in daylight vision and colour vision
        Fovea is a tiny spot in the retina that contains only cones, and has a high acuity
3. Pupil of the eye
  1. The opening in the iris that regulates amount of light passing into the eye
4. Optic Chiasm- the point at which the optic nerves from each eye cross over and project to the opposite side of the brain
  1. The main pathway projects to the thalamus
5. Colour
  1. Perceived colours is the function of dominant wavelengths
    1. Subtractive colour
      1. Removing some wavelengths of light, leaving less light than was originally there
    2. Additive colour
      1. Putting more light in the mixture than exists in any one light by itself
    3. Colour Theories
      1. Trichromatic Theory
        The human eye has three types of receptors with differing sensitivities to different light wavelengths
      2. Opponent Process Theory
        Colour perception depends on receptors that make antagonistic responses to three pairs of colours
      3. Reconciling Theory
        Realizing that the Trichromatic and opponent process theory are needed to explain colour vision
Auditory System
1. Sound waves are vibrations of molecules, moving at a fraction of the speed of light
  1. Characterized by their amplitude, wavelength, and purity. Affect perceived qualities of loudness, pitch, and timbre.
2. The ear is divided into three sections: the outer ear, the middle ear, and inner ear
  1. External ear depends on vibration of air molecules, middle ear depends on vibrations of movable bones, and inner ear depends on waves in a fluid.
    1. Inner ear consists of the cochlea- a fluid filled, coiled tunnel that contains hearing receptors.
      1. Basilar membrane runs along the spiralled cochlea and holds auditory receptors (hair cells).
        Sound signals routed to the thalamus, then auditory cortex in the temporal lobes
3. Theories of Hearing
  1. Place Theory
    1. Perception of pitch corresponds to the rate or frequency, at which the basilar membrane vibrates
  2. Frequency Theory
    1. Perception of pitch corresponds to rate or frequency at which the basilar membrane vibrates
  3. Both theories are valid, but slightly flawed
    1. Place theory was on the mark except that hair cells vibrate together as suggested by frequency theory

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Sensation and Perception

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	Erstellt von Kristen Thorpe vor fast 8 Jahre