Psychology Chp. 3

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Psychology Chp. 3
2010-02-25 00:08:01
Sensation and Perception

Operation of Sensory systems
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  1. Sense
    translates info from outside nervous system into neural activity giving nervous system knowledge of the world (initial message, not interpretation)
  2. operation of sensory systems
    • 1. accessory structures
    • 2. transduction
    • 3. info relayed to thalamus
    • 4. thalamus reroutes to appropriate place
    • 5. interpretation of stimulus
  3. accessory structures (ear, lens in eye)
    captures and modifies stimulus energy
  4. transduction
    process that transforms physical energy into electrochemical signals (done w/ receptors)
  5. thalamus
    relay station for pain and sense-organ signals
  6. detection threshold
    smallest amount of energy required for person to report a stimulus on half of the trials
  7. signal detection
    assesses persons sensitivity to stimulus and criterion for saying they detect a stimulus
  8. Weber's law
    difference threshold proportional to intensity of the stimulus
  9. difference threshold
    point at which pair of stimuli are recognized as being different half of the time
  10. coding
    translation of physical properties of stimulus into a unique pattern of neural activity (specifically identifies particular physical properties)
  11. feature detectors
    code physical properties of stimuli by responding to very specific features located in a more complex stimulus (responds to a unique code)
  12. Cornea
    transparent bulge on the front of eye (light enters here)
  13. Pupil
    an opening in the iris (light passes through pupil)
  14. Iris
    muscular disk controls amount of light entering eye
  15. Lens
    elastic membrane capsule
  16. Thin lens
    focus on distant objects
  17. Thicker lens
    focus on nearby objects
  18. Nearsightedness
    • difficulty focusing on distant objects
    • eyeball is too long and so focuses light rays in front of the retina
  19. Farsightedness
    • difficulty focusing clearly on near objects
    • eyeball is too short and so light rays focus behind the retina
  20. Retina
    • multilayered tissue located at rear of eyeball
    • contains photoreceptors
  21. Photoreceptors
    • specialized nerve cells
    • convert light energy into neural responses
  22. Rods
    black and white receptors - function best in dim light
  23. Cones
    color receptors - function best in bright light
  24. Optic nerve
    carries neural signals to thalamus and then occipital lobe
  25. color is the result of
    light from different mixtures of wavelengths
  26. Theories of Color Vision
    • Trichromatic
    • Dual process theory
  27. Trichromatic (Young-Helmholtz)
    any color can be matched by mixing lights of 3 wavelengths: blue, green and red (3 types of color receptors in retina)
  28. Dual process theory
    • color processing occurs in 2 stages
    • 1. retina's red/green/blue cones respond in varying degrees to light wavelengths
    • 2. ganglion cells combine output of cones into red-green, blue-yellow, and black-white information
  29. Color deficiency
    • Red or green sensitive cones done function properly
    • vision is dichromatic instead of trichromatic
    • difficut to distinguish red and green
  30. perception
    process of how sensations are interpreted as meaningful experiences (compares w/ previous info)
  31. 3 types of processing
    • bottom-up
    • feature
    • top down
  32. Bottom up processing
    taking individual elements of stimulus and combining into unified whole
  33. feature detectors
    respond to selected, basic features of a stimulus - features recombined to create the perceptual whole
  34. Top down processing
    sensory information is interpreted in light of existing knowledge, ideas, and expectiation (prior experiences)
  35. Figure-ground
    organize stimuli into a foreground figure and a background
  36. grouping
    • tend to perceive objects as groups rather than individual units:
    • proximity - nearness
    • similarity - likeness
    • closure - incomplete figures as complete
  37. Size and shape constancy
    perceived size/shape of objects remain same despite changes retinal image
  38. linear perspective
    parallel lines that are distant appear to converge toward a point on the horizon
  39. relative size
    distant object appears smaller than does same object close up
  40. How do we perceive objects as 3D when retinal image is 2D
    depth cues
  41. stroboscopic motion
    perception of motion from series of "snapshot" images - each slightly different from previous one
  42. Phi phenomenon
    series of lights flas on and off sequentially at alightly different locations - "moving light"
  43. ability to experience environmental stimuli
  44. we receive info from our environment through
    vision, hearing, taste, touch, and smell
  45. specialized nerve cells that detect stimuli in environment and are responsible for transduction
    sensory receptors
  46. sensory receptors for smell
    olfactory receptors
  47. our formed disposition based on our life experiences
    perceptual set (schema)
  48. what influences your perception
    what you are expecting
  49. the ability to attend to the things that are of interest to us by filtering stimuli
    selective attention