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Sensation & Perception

혼잣말
[Terms]
  • Sensation: The activation of the sense organs by a source of physical energy
    • bottom-up process, receive and relay outside stimuli
  • Perception: The sorting out, interpretation, analysis, and integration of stimuli carried out by the sense organs and brain.
    • top-down way our brains organize and interpret
  • Stimuli: any passing source of physical energy that produces a response in a sense organ.
    • ex) light stimuli, sound stimuli.
    • differ in intensity and type.
  • Remember that sensation refers to the activation of the sense organs (a physical response), whereas perception refers to how stimuli are interpreted (a psychological response).



  • Absolute Threshold: The smallest intensity of a stimulus that must be present for the stimulus to be detected. “fifty-percent"
    • Noise: background stimulation that interferes with the perception of other stimuli. (not just “hearing” noise)
  • Difference threshold, or just noticeable difference: The smallest level of added or reduced stimulation required to sense that a change in stimulation has occurred.
  • Weber’s law: Just noticeable difference is a constant proportion to the intensity of an initial stimulus
    • ex) weight - 1:50 (it takes a 1oz increase in a 50 oz weight to produce a noticeable difference, 10oz increase in a 500 oz weight)



  • Sensory Adaptation: An adjustment in sensory capacity after prolonged exposure to unchanging stimuli.
    • happens due to the inability of the sensory nerve receptors to fire off messages to the brain indefinitely
    • constant stimulation is not effective in producing a sustained reaction, because the receptors are most responsive to changes in stimulation.




[Vision]
Neurology of Vision explained in Crash Course (https://youtu.be/unWnZvXJH2o?t=4m23s)


  • feature detection: The activation of neutrons in the cortex by visual stimuli of specific shapes or patterns



Color Vision
  • Young-Helmholtz Trichromatic theory: There are 3 kinds of cones in the retina, each of which responds primarily to a specific range of wavelengths
    • does not explain afterimage,
  • Opponent-process theory: Receptor cells for color are linked in pairs, working in opposition to each other.





Sound
  • Place theory: different areas of the basilar membrane respond to different frequencies