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  1. 1. 1 PSYCHOLOGY (9th Edition) David Myers PowerPoint Slides Aneeq Ahmad Henderson State University Worth Publishers, © 2010
  2. 2. 2 Sensation and Perception Chapter 6
  3. 3. 3 Sensation Sensing the World: Some Basic Principles  Thresholds  Sensory Adaptation Vision  The Stimulus Input: Light Energy  The Eye  Visual Information Processing  Color Vision
  4. 4. 4 Hearing  The Stimulus Input: Sound Waves  The Ear  Hearing Loss and Deaf Culture Other Important Senses  Touch  Pain  Taste  Smell
  5. 5. 5 Perceptual Organization  Form Perception  Depth Perception  Motion Perception  Perceptual Constancy
  6. 6. 6 Perceptual Interpretation  Sensory Deprivation and Restored Vision  Perceptual Adaptation  Perceptual Set  Perception and the Human Factor
  7. 7. 7 Is There Extrasensory Perception?  Claims of ESP  Premonitions or Pretensions?  Putting ESP to Experimental Test
  8. 8. 8 Sensation & Perception How do we construct our representations of the external world? To represent the world, we must detect physical energy (a stimulus) from the environment and convert it into neural signals. This is a process called sensation. When we select, organize, and interpret our sensations, the process is called perception.
  9. 9. 9 Bottom-up Processing Analysis of the stimulus begins with the sense receptors and works up to the level of the brain and mind. Letter “A” is really a black blotch broken down into features by the brain that we perceive as an “A.”
  10. 10. 10 Top-Down Processing Information processing guided by higher-level mental processes as we construct perceptions, drawing on our experience and expectations. THE CHT
  11. 11. 11 Our sensory and perceptual processes work together to help us sort out complex images. Making Sense of Complexity “The Forest Has Eyes,” Bev Doolittle
  12. 12. 12 Sensing the World Senses are nature’s gift that suit an organism’s needs. A frog feeds on flying insects; a male silkworm moth is sensitive to female sex-attractant odor; and we as human beings are sensitive to sound frequencies that represent the range of human voice.
  13. 13. 13 Exploring the Senses What stimuli cross our threshold for conscious awareness?
  14. 14. 14 Psychophysics A study of the relationship between physical characteristics of stimuli and our psychological experience with them. Physical World Psychological World Light Brightness Sound Volume Pressure Weight Sugar Sweet
  15. 15. 15 Thresholds Absolute Threshold: Minimum stimulation needed to detect a particular stimulus 50% of the time. Proportionof“Yes”Responses 0.000.501.00 0 5 10 15 20 25 Stimulus Intensity (lumens)
  16. 16. 16 Subliminal Threshold Subliminal Threshold: When stimuli are below one’s absolute threshold for conscious awareness. KurtScholz/Superstock
  17. 17. 17 Weber’s Law Two stimuli must differ by a constant minimum percentage (rather than a constant amount), to be perceived as different. Weber fraction: k = δI/I. Stimulus Constant (k) Light 8% Weight 2% Tone 3%
  18. 18. 18 Sensory Adaptation Diminished sensitivity as a consequence of constant stimulation. Put a band aid on your arm and after awhile you don’t sense it.
  19. 19. 19 Now you see, now you don’t
  20. 20. 20 Vision
  21. 21. 21 Transduction In sensation, the transformation of stimulus energy (sights, sounds, smells) into neural impulses.
  22. 22. 22 Visible Spectrum The Stimulus Input: Light EnergyBothPhotos:ThomasEisner
  23. 23. 23 Physical Characteristics of Light 1. Wavelength (hue/color) 2. Intensity (brightness)
  24. 24. 24 Wavelength (Hue) Hue (color) is the dimension of color determined by the wavelength of the light. Wavelength is the distance from the peak of one wave to the peak of the next.
  25. 25. 25 Wavelength (Hue) Different wavelengths of light result in different colors. 400 nm 700 nm Long wavelengthsShort wavelengths Violet Indigo Blue Green Yellow Orange Red
  26. 26. 26 Intensity (Brightness) Intensity: Amount of energy in a wave determined by the amplitude. It is related to perceived brightness.
  27. 27. 27 Intensity (Brightness) Blue color with varying levels of intensity. As intensity increases or decreases, blue color looks more “washed out” or “darkened.”
  28. 28. 28 The Eye
  29. 29. 29 Parts of the eye 1. Cornea: Transparent tissue where light enters the eye. 2. Iris: Muscle that expands and contracts to change the size of the opening (pupil) for light. 3. Lens: Focuses the light rays on the retina. 4. Retina: Contains sensory receptors that process visual information and sends it to the brain.
  30. 30. 30 The Lens Lens: Transparent structure behind the pupil that changes shape to focus images on the retina. Accommodation: The process by which the eye’s lens changes shape to help focus near or far objects on the retina.
  31. 31. 31 Retina Retina: The light- sensitive inner surface of the eye, containing receptor rods and cones in addition to layers of other neurons (bipolar, ganglion cells) that process visual information.
  32. 32. 32 Optic Nerve, Blind Spot & Fovea http://www.bergen.org Optic nerve: Carries neural impulses from the eye to the brain. Blind Spot: Point where the optic nerve leaves the eye because there are no receptor cells located there. Fovea: Central point in the retina around which the eye’s cones cluster.
  33. 33. 33 Test your Blind Spot Use your textbook. Close your left eye, and fixate your right eye on the black dot. Move the page towards your eye and away from your eye. At some point the car on the right will disappear due to a blind spot.
  34. 34. 34 Photoreceptors E.R. Lewis, Y.Y. Zeevi, F.S Werblin, 1969
  35. 35. 35 Bipolar & Ganglion Cells Bipolar cells receive messages from photoreceptors and transmit them to ganglion cells, which converge to form the optic nerve.
  36. 36. 36 Visual Information Processing Optic nerves connect to the thalamus in the middle of the brain, and the thalamus connects to the visual cortex.
  37. 37. 37 Feature Detection Nerve cells in the visual cortex respond to specific features, such as edges, angles, and movement. RossKinnaird/Allsport/GettyImages
  38. 38. 38 Shape Detection Specific combinations of temporal lobe activity occur as people look at shoes, faces, chairs and houses. Ishai,Ungerleider,MartinandHaxby/NIMH
  39. 39. 39 Visual Information Processing Processing of several aspects of the stimulus simultaneously is called parallel processing. The brain divides a visual scene into subdivisions such as color, depth, form, movement, etc.
  40. 40. 40 From Sensation to Recognition
  41. 41. 41 Color Vision Trichromatic theory: Young and von Helmholtz suggested that the eye must contain three receptors that are sensitive to red, blue and green colors. Blue Green Red Medium LowMax Standard stimulus Comparison stimulus
  42. 42. 42 Color Blindness Ishihara Test Genetic disorder in which people are blind to green or red colors. This supports the Trichromatic theory.
  43. 43. 43 Opponent Colors Gaze at the middle of the flag for about 30 Seconds. When it disappears, stare at the dot and report whether or not you see Britain's flag.
  44. 44. 44 Hearing
  45. 45. 45 Hearing The Stimulus Input: Sound Waves Sound waves are compressing and expanding air molecules.
  46. 46. 46 Sound Characteristics 1. Frequency (pitch) 2. Intensity (loudness)
  47. 47. 47 The Ear Dr.FredHossler/VisualsUnlimited
  48. 48. 48 The Ear Outer Ear: Collects and sends sounds to the eardrum. Middle Ear: 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. Inner Ear: Innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs.
  49. 49. 49 Cochlea Cochlea: Coiled, bony, fluid-filled tube in the inner ear that transforms sound vibrations to auditory signals.
  50. 50. 50 Intensity (Loudness) Intensity (Loudness): Amount of energy in a wave, determined by the amplitude, relates to the perceived loudness.
  51. 51. 51 Loudness of Sound 70dB 120dB RichardKaylin/Stone/GettyImages
  52. 52. 52 Frequency (Pitch) Frequency (pitch): The dimension of frequency determined by the wavelength of sound. Wavelength: The distance from the peak of one wave to the peak of the next.
  53. 53. 53 Localization of Sounds Because we have two ears, sounds that reach one ear faster than the other ear cause us to localize the sound.
  54. 54. 54 Localization of Sound 1. Intensity differences 2. Time differences Time differences as small as 1/100,000 of a second can cause us to localize sound. The head acts as a “shadow” or partial sound barrier.
  55. 55. 55 Touch The sense of touch is a mix of four distinct skin senses—pressure, warmth, cold, and pain. BruceAyers/Stone/GettyImages
  56. 56. 56 Skin Senses Only pressure has identifiable receptors. All other skin sensations are variations of pressure, warmth, cold and pain. Burning hot Pressure Vibration Vibration Cold, warmth and pain
  57. 57. 57 Pain Pain tells the body that something has gone wrong. Usually pain results from damage to the skin and other tissues. A rare disease exists in which the afflicted person feels no pain. Ashley Blocker (right) feels neither pain nor extreme hot or cold. APPhoto/StephenMorton
  58. 58. 58 Biopsychosocial Influences
  59. 59. 59 Gate-Control Theory Melzack and Wall (1965, 1983) proposed that our spinal cord contains neurological “gates” that either block pain or allow it to be sensed. GaryComer/PhototakeUSA.com
  60. 60. 60 Pain Control Pain can be controlled by a number of therapies including, drugs, surgery, acupuncture, exercise, hypnosis, and even thought distraction. ToddRichardsandAricVills,U.W. ©HunterHoffman,www.vrpain.com
  61. 61. 61 Taste Traditionally, taste sensations consisted of sweet, salty, sour, and bitter tastes. Recently, receptors for a fifth taste have been discovered called “Umami”. Sweet Sour Salty Bitter Umami (Fresh Chicken)
  62. 62. 62 Sensory Interaction When one sense affects another sense, sensory interaction takes place. So, the taste of strawberry interacts with its smell and its texture on the tongue to produce flavor.
  63. 63. 63 Smell Like taste, smell is a chemical sense. Odorants enter the nasal cavity to stimulate 5 million receptors to sense smell. Unlike taste, there are many different forms of smell.
  64. 64. 64 Smell and Memories The brain region for smell (in red) is closely connected with the brain regions involved with memory (limbic system). That is why strong memories are made through the sense of smell.
  65. 65. 65 Body Position and Movement The sense of our body parts’ position and movement is called kinesthesis. The vestibular sense monitors the head (and body’s) position. http://www.heyokamagazine.com Whirling Dervishes Wire Walk BobDaemmrich/TheImageWorks
  66. 66. 66 Perceptual Organization How do we form meaningful perceptions from sensory information? We organize it. Gestalt psychologists showed that a figure formed a “whole” different than its surroundings.
  67. 67. 67 Organization of the visual field into objects (figures) that stand out from their surroundings (ground). Form Perception TimeSavingsSuggestion,©2003RogerSheperd.
  68. 68. 68 Grouping After distinguishing the figure from the ground, our perception needs to organize the figure into a meaningful form using grouping rules.
  69. 69. 69 Grouping & Reality Although grouping principles usually help us construct reality, they may occasionally lead us astray. BothphotosbyWalterWick.ReprintedfromGAMES Magazine..©1983PCSGamesLimitedPartnership
  70. 70. 70 Depth Perception Visual Cliff Depth perception enables us to judge distances. Gibson and Walk (1960) suggested that human infants (crawling age) have depth perception. Even newborn animals show depth perception. Innervisions
  71. 71. 71 Binocular Cues Retinal disparity: Images from the two eyes differ. Try looking at your two index fingers when pointing them towards each other half an inch apart and about 5 inches directly in front of your eyes. You will see a “finger sausage” as shown in the inset.
  72. 72. 72 Monocular Cues Relative Size: If two objects are similar in size, we perceive the one that casts a smaller retinal image to be farther away.
  73. 73. 73 Monocular Cues Interposition: Objects that occlude (block) other objects tend to be perceived as closer. ReneMagritte,TheBlankSignature,oiloncanvas, NationalGalleryofArt,Washington.Collectionof Mr.andMrs.PaulMellon.PhotobyRichardCarafelli.
  74. 74. 74 Monocular Cues Relative Height: We perceive objects that are higher in our field of vision to be farther away than those that are lower. ImagecourtesyofShaunP.Vecera,Ph.D., adaptedfromstimulithatapperedinVecreraetal.,2002
  75. 75. 75 Monocular Cues Relative motion: Objects closer to a fixation point move faster and in opposing direction to those objects that are farther away from a fixation point, moving slower and in the same direction.
  76. 76. 76 Monocular Cues Linear Perspective: Parallel lines, such as railroad tracks, appear to converge in the distance. The more the lines converge, the greater their perceived distance. ©TheNewYorkerCollection,2002,JackZiegler fromcartoonbank.com.Allrightsreserved.
  77. 77. 77 Monocular Cues Light and Shadow: Nearby objects reflect more light into our eyes than more distant objects. Given two identical objects, the dimmer one appears to be farther away. From“PerceivingShapeFromShading”byVilayaur S.Ramachandran.©1988byScientificAmerican,Inc. Allrightsreserved.
  78. 78. 78 Perceptual Constancy Perceiving objects as unchanging even as illumination and retinal images change.
  79. 79. 79 Perceiving familiar objects as having consistent color even when changing illumination filters the light reflected by the object. Color Constancy Color Constancy
  80. 80. 80 Size-Distance Relationship The distant monster (below, left) and the top red bar (below, right) appear bigger because of distance cues. FromShepard,1990 AlanChoisnet/TheImageBank
  81. 81. 81 Size-Distance Relationship Both girls in the room are of similar height. However, we perceive them to be of different heights as they stand in the two corners of the room. Both photos from S. Schwartzenberg/ The Exploratorium
  82. 82. 82 Ames Room The Ames room is designed to demonstrate the size- distance illusion.
  83. 83. 83 Lightness Constancy The color and brightness of square A and B are the same. Courtesy EdwardAdelson
  84. 84. 84 Perceptual Interpretation Immanuel Kant (1724-1804) maintained that knowledge comes from our inborn ways of organizing sensory experiences. John Locke (1632-1704) argued that we learn to perceive the world through our experiences. How important is experience in shaping our perceptual interpretation?
  85. 85. 85 Sensory Deprivation & Restored Vision After cataract surgery, blind adults were able to regain sight. These individuals could differentiate figure and ground relationships, yet they had difficulty distinguishing a circle and a triangle (Von Senden, 1932).
  86. 86. 86 Facial Recognition After blind adults regained sight, they were able to recognize distinct features, but were unable to recognize faces. Normal observers also show difficulty in facial recognition when the lower half of the pictures are changed. CourtesyofRichardLeGrand
  87. 87. 87 Kittens raised without exposure to horizontal lines later had difficulty perceiving horizontal bars. Blakemore & Cooper (1970) Sensory Deprivation
  88. 88. 88 Perceptual Adaptation Visual ability to adjust to an artificially displaced visual field, e.g., prism glasses. CourtesyofHubertDolezal
  89. 89. 89 Perceptual Set A mental predisposition to perceive one thing and not another. What you see in the center picture is influenced by flanking pictures. FromShepard,1990.
  90. 90. 90 (a) Loch ness monster or a tree trunk; (b) Flying saucers or clouds? Perceptual Set Other examples of perceptual set. FrankSearle,photoAdams/Corbis-Sygma DickRuhl
  91. 91. 91 Is the “magician cabinet” on the floor or hanging from the ceiling? Context Effects Context can radically alter perception.
  92. 92. 92 To an East African, the woman sitting is balancing a metal box on her head, while the family is sitting under a tree. Cultural Context Context instilled by culture also alters perception.
  93. 93. 93 Perception Revisited Is perception innate or acquired?
  94. 94. 94 Is There Extrasensory Perception? Perception without sensory input is called extrasensory perception (ESP). A large percentage of scientists do not believe in ESP.
  95. 95. 95 Claims of ESP 1. Telepathy: Mind-to-mind communication. One person sending thoughts and the other receiving them. 2. Clairvoyance: Perception of remote events, such as sensing a friend’s house on fire. 3. Precognition: Perceiving future events, such as a political leader’s death. Psychokinesis The power of “mind over matter” such as levitating a table/influencing a role of the die.

Notes de l'éditeur

  • Preview Question 1: What are sensation and perception? What do we mean by bottom-up processing and top-down processing?
  • Preview Question 2: What is are the absolute and difference thresholds, and do stimuli below the absolute threshold have any influence?
  • Preview Question 3: What is the function of sensory adaptation?
  • Preview Question 4: What are the energy that we see as visible light?
  • Preview Question 5: How does the eye transform light energy into neural messages?
  • Preview Question 6: How does the brain process visual information?
  • Preview Question 7: What theories help us understand color vision?
  • Preview Question 8: What are the characteristics of air pressure waves that we hear as sound?
  • Preview Question 9: How does the ear transform sound energy into neural messages?
  • Preview Question 10: What theories help us understand pitch perception?
  • Preview Question 11: How do we locate sounds?
  • Preview Question 12: What are the common causes of hearing loss, and why does controversy surround cochlear implants?
  • Preview Question 13: How do we sense touch and sense our body’s position and movement? How do we experience pain?
  • Preview Question 14: How do we experience taste?
  • Preview Question 15: How do we experience smell?
  • Preview Question 16: How did the Gestalt psychologists understand perceptual organization?
  • Preview Question 17: How do figure-ground and grouping principles contribute to our perceptions?
  • Preview Question 18: How do we see the world in three dimensions?
  • Preview Question 19: How do we perceive motion?
  • Preview Question 20: How do perceptual constancies help us to organize our sensations into meaningful perceptions?
  • Preview Question 21: What does research on sensory restriction and restored vision reveal about the effects of experience?
  • Preview Question 22: How adaptable is our ability to perceive?
  • Preview Question 23: How do our expectations, contexts, and emotions influence our perceptions?
  • Preview Question 24: How do human factors psychologists work to create user-friendly machines and work settings?
  • Preview Question 25: What are the claims of ESP, and what have most research psychologists concluded after putting these claims to the test?