Sensation & Perception PowerPoint

44,267 views

Published on

Published in: Sports, Technology
15 Comments
72 Likes
Statistics
Notes
No Downloads
Views
Total views
44,267
On SlideShare
0
From Embeds
0
Number of Embeds
406
Actions
Shares
0
Downloads
0
Comments
15
Likes
72
Embeds 0
No embeds

No notes for slide

Sensation & Perception PowerPoint

  1. 1. Sensation and Perception chapter 6
  2. 2. Overview <ul><li>Our sensational senses </li></ul><ul><li>Vision </li></ul><ul><li>Hearing </li></ul><ul><li>Other senses </li></ul><ul><li>Perceptual powers </li></ul><ul><li>Puzzles of perception </li></ul>chapter 6
  3. 3. Definitions <ul><li>Sensation </li></ul><ul><li>The detection of physical energy emitted or reflected by physical objects </li></ul><ul><li>Occurs when energy in the external environment or the body stimulates receptors in the sense organs </li></ul><ul><li>Perception </li></ul><ul><li>The process by which the brain organizes and interprets sensory information </li></ul>chapter 6
  4. 4. Ambiguous figure <ul><li>Colored surface can be either the outside front surface or the inside back surface. </li></ul><ul><li>But not simultaneously both </li></ul><ul><li>The brain can interpret the ambiguous cues in two different ways. </li></ul>chapter 6
  5. 5. Riddle of separate sensations <ul><li>Sense receptors </li></ul><ul><li>Specialized cells that convert physical energy into electrical energy that can be transmitted as nerve impulses to the brain </li></ul>chapter 6
  6. 6. Sensation and perception chapter 6
  7. 7. Specific nerve energies <ul><li>Different sensory modalities exist because signals received by the sense organs stimulate different nerve pathways leading to different areas of the brain. </li></ul><ul><li>Synesthesia </li></ul><ul><li>A condition in which stimulation of one sense also evokes another </li></ul>chapter 6
  8. 8. Absolute threshold <ul><li>The smallest quantity of physical energy that can be reliably detected by an observer </li></ul>chapter 6
  9. 9. Absolute thresholds <ul><li>Vision </li></ul><ul><li>A single candle flame from 30 miles on a clear night </li></ul><ul><li>Hearing </li></ul><ul><li>The tick of a watch from 20 feet in total quiet </li></ul><ul><li>Smell </li></ul><ul><li>One drop of perfume in a 6-room apartment </li></ul><ul><li>Touch </li></ul><ul><li>The wing of a bee on the cheek, dropped from 1 cm </li></ul><ul><li>Taste </li></ul><ul><li>One teaspoon of sugar in 2 gallons of water </li></ul>chapter 6
  10. 10. Difference threshold <ul><li>The smallest difference in stimulation that can be reliably detected by an observer when two stimuli are compared </li></ul><ul><li>Also called the Just Noticeable Difference (JND) </li></ul>chapter 6
  11. 11. Signal-detection theory <ul><li>A psychophysical theory that divides the detection of a sensory signal into a sensory process and a decision process </li></ul>chapter 6
  12. 12. Sensory adaptation and deprivation <ul><li>Adaptation </li></ul><ul><li>The reduction or disappearance of sensory responsiveness when stimulation is unchanging or repetitious </li></ul><ul><li>Prevents us from having to respond continuously to unimportant information </li></ul><ul><li>Deprivation </li></ul><ul><li>The absence of normal levels of sensory stimulation </li></ul>chapter 6
  13. 13. Sensory overload <ul><li>Over-stimulation of the senses </li></ul><ul><li>Can use selective attention to reduce sensory overload </li></ul><ul><li>Selective attention: the focusing of attention on selected aspects of the environment and the blocking out of others </li></ul>chapter 6
  14. 14. Vision <ul><li>What we see </li></ul><ul><li>An eye on the world </li></ul><ul><li>Why the visual system is not a camera </li></ul><ul><li>How we see colors </li></ul><ul><li>Constructing the visual world </li></ul>chapter 6
  15. 15. What we see <ul><li>Hue </li></ul><ul><li>Visual experience specified by color names and related to the wavelength of light </li></ul><ul><li>Brightness </li></ul><ul><li>Visual experience related to the amount of light emitted from or reflected by an object </li></ul><ul><li>Saturation </li></ul><ul><li>Visual experience related to the complexity of light waves </li></ul>chapter 6
  16. 16. What we see chapter 6
  17. 17. An eye on the world <ul><li>Cornea </li></ul><ul><li>Protects eye and bends light toward lens </li></ul><ul><li>Lens </li></ul><ul><li>Focuses on objects by changing shape </li></ul><ul><li>Iris </li></ul><ul><li>Controls amount of light that gets into eye </li></ul><ul><li>Pupil </li></ul><ul><li>Aperture through which light reaches the retina </li></ul>chapter 6
  18. 18. An eye on the world <ul><li>Retina </li></ul><ul><li>Neural tissue lining the back of the eyeball’s interior containing the receptors for vision </li></ul><ul><li>Rods </li></ul><ul><li>Visual receptors that respond to dim light </li></ul><ul><li>Cones </li></ul><ul><li>Visual receptors involved in color vision </li></ul>chapter 6
  19. 19. Structures of the retina chapter 6
  20. 20. Your turn <ul><li>You have a hard time locating your red car at night, in the poorly lit mall parking lot. Why? </li></ul><ul><li>1. Your rods are less sensitive to color in dim light. </li></ul><ul><li>2. Your cones, which detect color, do not function well in dim light. </li></ul><ul><li>3. Your ganglion cells receive insufficient overall stimulation to </li></ul><ul><li>function. </li></ul><ul><li>4. Your rods, which detect color, do not function well in dim light. </li></ul>chapter 6
  21. 21. Your turn <ul><li>You have a hard time locating your red car at night, in the poorly lit mall parking lot. Why? </li></ul><ul><li>1. Your rods are less sensitive to color in dim light. </li></ul><ul><li>2. Your cones, which detect color, do not function well in dim light. </li></ul><ul><li>3. Your ganglion cells receive insufficient overall stimulation to </li></ul><ul><li>function. </li></ul><ul><li>4. Your rods, which detect color, do not function well in dim light. </li></ul>chapter 6
  22. 22. The visual system is not a camera <ul><li>Much visual processing is done in the brain </li></ul><ul><li>Some cortical cells respond to lines in specific orientations (e.g., horizontal). </li></ul><ul><li>Other cortical cells respond to other shapes (e.g., bulls-eyes, spirals, faces). </li></ul><ul><li>Feature detectors </li></ul><ul><li>Cells in the visual cortex that are sensitive to specific features of the environment </li></ul>chapter 6
  23. 23. Huble and Wiesel’s experiment chapter 6
  24. 24. Trichromatic theory <ul><li>Young (1802) and von Helmholtz (1852) both proposed that the eye detects 3 primary colors </li></ul><ul><li>Red, blue, and green </li></ul><ul><li>All other colors derived by combination </li></ul>chapter 6
  25. 25. Opponent-process theory <ul><li>A competing theory of color vision, which assumes that the visual system treats pairs of colors as opposing or antagonistic </li></ul><ul><li>Opponent-process cells are inhibited by a color, and have a burst of activity when it is removed. </li></ul>chapter 6
  26. 26. Form perception <ul><li>Gestalt principles describe the brain’s organization of sensory building blocks into meaningful units and patterns. </li></ul>chapter 6
  27. 27. Gestalt principles <ul><li>Proximity </li></ul><ul><li>Things close to one another are grouped together </li></ul><ul><li>Closure </li></ul><ul><li>The brain tends to fill in gaps to perceive complete forms </li></ul>chapter 6
  28. 28. Gestalt principles <ul><li>Similarity </li></ul><ul><li>Things that are alike are perceived together </li></ul><ul><li>Continuity </li></ul><ul><li>Seeing continuity in lines that could be interpreted as either continuous or abruptly shifting in direction. </li></ul>chapter 6
  29. 29. Your turn <ul><li>Which Gestalt principle is illustrated by the fact that we see columns of dots rather than rows in this diagram? </li></ul><ul><li>1. Similarity </li></ul><ul><li>2. Proximity </li></ul><ul><li>3. Closure </li></ul><ul><li>4. Continuity </li></ul>chapter 6
  30. 30. Your turn <ul><li>Which Gestalt principle is illustrated by the fact that we see columns of dots rather than rows in this diagram? </li></ul><ul><li>1. Similarity </li></ul><ul><li>2. Proximity </li></ul><ul><li>3. Closure </li></ul><ul><li>4. Continuity </li></ul>chapter 6
  31. 31. Depth and distance perception <ul><li>Binocular cues: visual cues that require the use of both eyes </li></ul><ul><li>Convergence </li></ul><ul><li>Turning inward of the eyes, which occurs when they focus on a nearby object </li></ul><ul><li>Retinal disparity </li></ul><ul><li>The slight difference in lateral separation between two objects as seen by the right and left eyes </li></ul>chapter 6
  32. 32. Depth and distance perception <ul><li>Monocular cues: visual cues that can be used by one eye </li></ul>chapter 6
  33. 33. Visual constancies <ul><li>The accurate perception of objects as stable or unchanged despite changes in the sensory patterns they produce </li></ul><ul><li>Shape constancy </li></ul><ul><li>Location constancy </li></ul><ul><li>Size constancy </li></ul><ul><li>Brightness constancy </li></ul><ul><li>Color constancy </li></ul>chapter 6
  34. 34. The Müller-Lyer illusion chapter 6
  35. 35. Fooling the eye <ul><li>The cats in (a) are the same size. </li></ul><ul><li>The diagonal lines in (b) are parallel. </li></ul><ul><li>You can create a “floating fingertip frankfurter” by holding hands as shown, 5–10 inches in front of face. </li></ul>chapter 6
  36. 36. What we hear <ul><li>Loudness </li></ul><ul><li>The dimension of auditory experience related to the intensity of a pressure wave </li></ul><ul><li>Pitch </li></ul><ul><li>The dimension of auditory experience related to the frequency of a pressure wave </li></ul><ul><li>Timbre </li></ul><ul><li>The dimension of auditory experience related to the complexity of a pressure wave </li></ul>chapter 6
  37. 37. An ear on the world chapter 6
  38. 38. Auditory localization <ul><li>Sounds from different directions are not identical as they arrive at left and right ears. </li></ul><ul><li>Loudness </li></ul><ul><li>Timing </li></ul><ul><li>Phase </li></ul><ul><li>The brain calculates a sound’s location by using these differences. </li></ul>chapter 6
  39. 39. Other senses <ul><li>Taste: savory sensations </li></ul><ul><li>Smell: the sense of scents </li></ul><ul><li>Senses of the skin </li></ul><ul><li>The mystery of pain </li></ul><ul><li>The environment within </li></ul>chapter 6
  40. 40. Taste: savory sensations <ul><li>Taste buds </li></ul><ul><li>Nests of taste-receptor cells </li></ul>chapter 6
  41. 41. Five tastes <ul><li>Five basic tastes </li></ul><ul><li>Salty, sour, bitter, sweet, umami </li></ul><ul><li>Different people have different tastes based on: </li></ul><ul><li>Genetics </li></ul><ul><li>Culture </li></ul><ul><li>Learning </li></ul><ul><li>Food attractiveness </li></ul>chapter 6
  42. 42. Smell: the sense of scents <ul><li>Airborne chemical molecules enter the nose and circulate through the nasal cavity. </li></ul><ul><li>Vapors can also enter through the mouth and pass into nasal cavity. </li></ul><ul><li>Receptors on the roof of the nasal cavity detect these molecules. </li></ul>chapter 6
  43. 43. Sensitivity to touch chapter 6
  44. 44. Gate-control theory of pain <ul><li>Experience of pain depends in part on whether the pain gets past a neurological “gate” in the spinal cord. </li></ul>chapter 6
  45. 45. Gate-control theory revised <ul><li>The matrix of neurons in the brain is capable of generating pain (and other sensations) in the absence of signals from sensory nerves. </li></ul>chapter 6
  46. 46. The environment within <ul><li>Kinesthesis </li></ul><ul><li>The sense of body position and movement of body parts </li></ul><ul><li>Equilibrium </li></ul><ul><li>The sense of balance </li></ul><ul><li>Semicircular canals </li></ul><ul><li>Sense organs in the inner ear, which contribute to equilibrium by responding to rotation of the head </li></ul>chapter 6
  47. 47. The visual cliff <ul><li>Glass surface, with checkerboard underneath at different heights </li></ul><ul><li>Visual illusion of a cliff </li></ul><ul><li>Baby can’t fall </li></ul><ul><li>Mom stands across the gap. </li></ul><ul><li>Babies show increased attention over deep side at age 2 months, but aren’t afraid until about the age they can crawl. </li></ul>chapter 6
  48. 48. Critical period <ul><li>If infants miss out on experiences during a crucial period of time, perception will be impaired. </li></ul><ul><li>When adults who have been blind since birth have vision restored, they may not see well. </li></ul><ul><li>Other senses such as hearing may be influenced similarly. </li></ul>chapter 6
  49. 49. Psychological and cultural influences <ul><li>We are more likely to perceive something when we need it. </li></ul><ul><li>What we believe can affect what we perceive. </li></ul><ul><li>Emotions, such as fear, can influence perceptions of sensory information. </li></ul><ul><li>Expectations based on previous experiences can influence perception. </li></ul><ul><li>Perceptual set: a habitual way of perceiving, based on expectations </li></ul><ul><li>All are influenced by culture. </li></ul>chapter 6
  50. 50. Perception vs. persuasion <ul><li>Although subliminal priming can influence judgments and preferences, research doesn’t support its success in major levels of persuasion. </li></ul>chapter 6
  51. 51. Extrasensory perception <ul><li>The ability to perceive something without ordinary sensory information </li></ul><ul><li>Has not been scientifically demonstrated </li></ul>chapter 6

×