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  1. 1. Myers’ EXPLORING PSYCHOLOGY (6th Ed)‏ <ul><li>Chapter 5 </li></ul><ul><li>Sensation and Perception </li></ul>
  2. 3. Sensation <ul><li>Sensation </li></ul><ul><ul><li>a process by which our sensory receptors and nervous system receive and represent stimulus energy </li></ul></ul><ul><li>Perception </li></ul><ul><ul><li>a process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events </li></ul></ul>
  3. 5. Sensation <ul><li>Our sensory and perceptual processes work together to help us sort out complex processes </li></ul>
  4. 6. Sensation <ul><li>Bottom-Up Processing </li></ul><ul><ul><li>analysis that begins with the sense receptors and works up to the brain’s integration of sensory information </li></ul></ul><ul><li>Top-Down Processing </li></ul><ul><ul><li>information processing guided by higher-level mental processes </li></ul></ul><ul><ul><li>as when we construct perceptions drawing on our experience and expectations </li></ul></ul>
  5. 7. Sensation - Basic Principles <ul><li>Psychophysics </li></ul><ul><ul><li>study of the relationship between physical characteristics of stimuli and our psychological experience of them </li></ul></ul><ul><ul><li>Light - brightness </li></ul></ul><ul><ul><li>Sound - volume </li></ul></ul><ul><ul><li>Pressure - weight </li></ul></ul><ul><ul><li>Taste - sweetness </li></ul></ul>
  6. 9. Sensation - Thresholds <ul><li>Absolute Threshold </li></ul><ul><ul><li>minimum stimulation needed to detect a particular stimulus 50% of the time </li></ul></ul><ul><li>Difference Threshold </li></ul><ul><ul><li>minimum difference between two stimuli required for detection 50% of the time </li></ul></ul><ul><ul><li>just noticeable difference (JND)‏ </li></ul></ul>
  7. 10. Sensation - Thresholds <ul><li>Subliminal </li></ul><ul><ul><li>When stimuli are below one’s absolute threshold for conscious awareness </li></ul></ul>0 25 50 75 100 Low Absolute threshold Medium Intensity of stimulus Percentage of correct detections Subliminal stimuli
  8. 11. Sensation - Thresholds <ul><li>Weber’s Law - to perceive as different, two stimuli must differ by a constant minimum percentage </li></ul><ul><ul><li>light intensity- 8% </li></ul></ul><ul><ul><li>weight- 2% </li></ul></ul><ul><ul><li>tone frequency- 0.3% </li></ul></ul><ul><li>Sensory adaptation - diminished sensitivity as a consequence of constant stimulation </li></ul>
  9. 13. Vision - Stabilized Images on the Retina
  10. 14. Vision <ul><li>Wavelength </li></ul><ul><ul><li>the distance from the peak of one wave to the peak of the next </li></ul></ul><ul><li>Hue </li></ul><ul><ul><li>dimension of color determined by </li></ul></ul><ul><ul><li>wavelength of light </li></ul></ul><ul><li>Intensity </li></ul><ul><ul><li>amount of energy in a wave determined by </li></ul></ul><ul><ul><li>amplitude </li></ul></ul><ul><ul><ul><li>brightness </li></ul></ul></ul><ul><ul><ul><li>loudness </li></ul></ul></ul>
  11. 15. The spectrum of electromagnetic energy
  12. 16. Vision - Physical Properties of Waves Short wavelength=high frequency (bluish colors, high-pitched sounds)‏ Long wavelength=low frequency (reddish colors, low-pitched sounds)‏ Great amplitude (bright colors, loud sounds)‏ Small amplitude (dull colors, soft sounds)‏
  13. 17. Vision
  14. 18. Vision <ul><li>Accommodation - the process by which the eye’s lens changes shape to help focus near or far objects on the retina </li></ul><ul><li>Retina- the light-sensitive inner surface of the eye, containing receptor rods and cones plus layers of neurons that begin the processing of visual information </li></ul>
  15. 19. Retina’s Reaction to Light - Receptors <ul><li>Rods </li></ul><ul><ul><li>peripheral retina </li></ul></ul><ul><ul><li>detect black, white and gray </li></ul></ul><ul><ul><li>twilight or low light </li></ul></ul><ul><li>Cones </li></ul><ul><ul><li>near center of retina </li></ul></ul><ul><ul><li>fine detail and color vision </li></ul></ul><ul><ul><li>daylight or well-lit conditions </li></ul></ul>
  16. 20. Retina’s Reaction to Light <ul><li>Optic nerve </li></ul><ul><ul><li>carries neural impulses from the eye to the brain </li></ul></ul><ul><li>Blind Spot </li></ul><ul><ul><li>point at which the optic nerve leaves the eye, creating a “blind spot” because there are no receptor cells located there </li></ul></ul>
  17. 21. Retina’s Reaction to Light
  18. 23. Vision - Receptors Receptors in the Human Eye Cones Rods Number Location in retina Sensitivity in dim light Color sensitive? Yes Low Center 6 million No High Periphery 120 million
  19. 24. Pathways from the Eyes to the Visual Cortex
  20. 25. Visual Information Processing <ul><li>Feature Detectors </li></ul><ul><ul><li>nerve cells in the brain that respond to specific features </li></ul></ul><ul><ul><li>shape </li></ul></ul><ul><ul><li>angle </li></ul></ul><ul><ul><li>movement </li></ul></ul>Stimulus Cell’s responses
  21. 26. Visual Information Processing <ul><li>Parallel Processing </li></ul><ul><ul><li>simultaneous processing of several aspects of a problem simultaneously </li></ul></ul>
  22. 27. Visual Information Processing
  23. 28. Visual Information Processing <ul><li>Trichromatic (three color) Theory </li></ul><ul><ul><li>Young and Helmholtz </li></ul></ul><ul><ul><li>three different retinal color receptors </li></ul></ul><ul><ul><ul><li>red </li></ul></ul></ul><ul><ul><ul><li>green </li></ul></ul></ul><ul><ul><ul><li>blue </li></ul></ul></ul>
  24. 29. Color-Deficient Vision <ul><li>People who suffer red-green blindness have trouble perceiving the number within the design </li></ul>
  25. 30. Visual Information Processing <ul><li>Opponent-Process Theory - opposing retinal processes enable color vision </li></ul><ul><li>“ ON” “OFF” </li></ul><ul><li>red green </li></ul><ul><li>green red </li></ul><ul><li>blue yellow </li></ul><ul><li>yellow blue </li></ul><ul><li>black white </li></ul><ul><li>white black </li></ul>
  26. 31. Opponent Process - Afterimage Effect
  27. 32. Body Position and Movement <ul><li>Kinesthesis </li></ul><ul><ul><li>the system for sensing the position and movement of individual body parts </li></ul></ul><ul><li>Vestibular Sense </li></ul><ul><ul><li>the sense of body movement and position </li></ul></ul><ul><ul><li>including the sense of balance </li></ul></ul>
  28. 34. Perceptual Organization <ul><li>Gestalt </li></ul><ul><ul><li>organized whole </li></ul></ul><ul><ul><li>tendency to </li></ul></ul><ul><ul><li>integrate pieces of information into </li></ul></ul><ul><ul><li>meaningful wholes </li></ul></ul>
  29. 35. Perceptual Organization <ul><li>Figure and Ground-- organization of the visual field into objects (figures) that stand out from their surroundings (ground)‏ </li></ul>
  30. 36. Perceptual Organization- Gestalt <ul><li>Grouping </li></ul><ul><ul><li>the perceptual tendency to organize stimuli into coherent groups </li></ul></ul><ul><li>Grouping Principles </li></ul><ul><ul><li>proximity --group nearby figures together </li></ul></ul><ul><ul><li>similarity --group figures that are similar </li></ul></ul><ul><ul><li>continuity --perceive continuous patterns </li></ul></ul><ul><ul><li>closure --fill in gaps </li></ul></ul><ul><ul><li>connectedness --spots, lines, and areas are seen as unit when connected </li></ul></ul>
  31. 37. Perceptual Organization- Grouping Principles
  32. 38. Perceptual Organization- Closure <ul><li>Gestalt grouping principles are at work here. </li></ul>
  33. 39. Perceptual Organization- Depth Perception Visual Cliff
  34. 40. Perceptual Organization- Depth Perception <ul><li>Depth Perception </li></ul><ul><ul><li>ability to see objects in three dimensions </li></ul></ul><ul><ul><li>allows us to judge distance </li></ul></ul><ul><li>Binocular cues </li></ul><ul><ul><li>retinal disparity </li></ul></ul><ul><ul><ul><li>images from the two eyes differ </li></ul></ul></ul><ul><ul><ul><li>closer the object, the larger the disparity </li></ul></ul></ul><ul><ul><li>convergence </li></ul></ul><ul><ul><ul><li>neuromuscular cue </li></ul></ul></ul><ul><ul><ul><li>two eyes move inward for near objects </li></ul></ul></ul>
  35. 41. Perceptual Organization- Depth Perception <ul><li>Monocular Cues </li></ul><ul><ul><li>relative size </li></ul></ul><ul><ul><ul><li>smaller image is more distant </li></ul></ul></ul><ul><ul><li>interposition </li></ul></ul><ul><ul><ul><li>closer object blocks distant object </li></ul></ul></ul><ul><ul><li>relative clarity </li></ul></ul><ul><ul><ul><li>hazy object seen as more distant </li></ul></ul></ul><ul><ul><li>texture coarse --> close fine --> distant </li></ul></ul>
  36. 42. Perceptual Organization- Depth Perception <ul><li>Monocular Cues (cont.)‏ </li></ul><ul><ul><li>relative height </li></ul></ul><ul><ul><ul><li>higher objects seen as more distant </li></ul></ul></ul><ul><ul><li>relative motion </li></ul></ul><ul><ul><ul><li>closer objects seem to move faster </li></ul></ul></ul><ul><ul><li>linear perspective </li></ul></ul><ul><ul><ul><li>parallel lines converge with distance </li></ul></ul></ul><ul><ul><li>relative brightness </li></ul></ul><ul><ul><ul><li>closer objects appear brighter </li></ul></ul></ul>
  37. 43. Perceptual Organization- Depth Perception Relative Size
  38. 44. Perceptual Organization- Depth Perception Interposition
  39. 45. Perceptual Organization- Depth Perception Relative Height
  40. 46. Perceptual Organization- Depth Perception Light and Shadow
  41. 47. Perceptual Organization- Depth Perception Perspective Techniques
  42. 48. Perceptual Constancy <ul><li>Perceptual Constancy </li></ul><ul><ul><li>perceiving objects as unchanging even as illumination and retinal image change </li></ul></ul><ul><ul><ul><li>color </li></ul></ul></ul><ul><ul><ul><li>shape </li></ul></ul></ul><ul><ul><ul><li>size </li></ul></ul></ul>
  43. 49. Perceptual Organization
  44. 51. Perceptual Illusions
  45. 52. Perceptual Illusions
  46. 53. Perceptual Organization- Size-Distance Relationship
  47. 54. Perceptual Organization-Brightness Contrast
  48. 55. Perceptual Organization- Grouping Principles <ul><li>Gestalt grouping principles are at work here. </li></ul>
  49. 56. Perceptual Organization- Grouping Principles <ul><li>Impossible doghouse </li></ul>
  50. 57. Perceptual Interpretation <ul><li>Perceptual Adaptation </li></ul><ul><ul><li>(vision) ability to adjust to an artificially displaced visual field </li></ul></ul><ul><ul><ul><li>prism glasses </li></ul></ul></ul><ul><li>Perceptual Set </li></ul><ul><ul><li>a mental predisposition to perceive one thing and not another </li></ul></ul>
  51. 59. Audition <ul><ul><li>Visual Capture </li></ul></ul><ul><ul><ul><li>tendency for vision to dominate the other senses </li></ul></ul></ul><ul><ul><li>Audition </li></ul></ul><ul><ul><ul><li>the sense of hearing </li></ul></ul></ul><ul><ul><li>Frequency </li></ul></ul><ul><ul><ul><li>the number of complete wavelengths that pass a point in a given time </li></ul></ul></ul><ul><ul><li>Pitch </li></ul></ul><ul><ul><ul><li>a tone’s highness or lowness </li></ul></ul></ul><ul><ul><ul><li>depends on frequency </li></ul></ul></ul>
  52. 60. The Intensity of Some Common Sounds
  53. 61. Audition - The Ear
  54. 62. Audition - The Ear <ul><li>Middle Ear </li></ul><ul><ul><li>chamber between eardrum and cochlea containing three tiny bones (hammer, anvil, stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window </li></ul></ul><ul><li>Inner Ear </li></ul><ul><ul><li>innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs </li></ul></ul><ul><li>Cochlea </li></ul><ul><ul><li>coiled, bony, fluid-filled tube in the inner ear through which </li></ul></ul>
  55. 63. How We Locate Sounds
  56. 64. Pain <ul><li>Gate-Control Theory </li></ul><ul><ul><li>theory that the spinal cord contains a neurological “gate” that blocks pain signals or allows them to pass on to the brain </li></ul></ul><ul><ul><li>“ gate” opened by the activity of pain signals traveling up small nerve fibers </li></ul></ul><ul><ul><li>“ gate” closed by activity in larger fibers or by information coming from the brain </li></ul></ul>
  57. 65. Taste <ul><li>Taste Sensations </li></ul><ul><ul><li>sweet </li></ul></ul><ul><ul><li>sour </li></ul></ul><ul><ul><li>salty </li></ul></ul><ul><ul><li>bitter </li></ul></ul><ul><li>Sensory Interaction </li></ul><ul><ul><li>the principle that one sense may influence another </li></ul></ul><ul><ul><li>as when the smell of food influences its taste </li></ul></ul>
  58. 66. Smell Receptor cells in olfactory membrane Nasal passage Olfactory bulb Olfactory nerve