1. Sensation and Perception Chapter 4 page 78

2. The 5 senses ( sensory organs) Sight (eyes) Hearing (ears) Smell (nose) Touch (skin) Taste (tongue)

3. Your 3 senses Select 3 things from each sense that you could not live without. Select 1 from each that you could live without. Sights Sounds Tastes Feels Smells

4. Our Sensational Senses Defining sensation and perception The riddle of separate senses Measuring the senses Sensory adaptation Sensory overload

5. Chapter 4 section 1

6. Defining Sensation and Perception Sensation The detection of physical energy emitted or reflected by physical objects. It occurs when energy in the external environment or the body stimulates receptors in the sense organs. Perception The process by which the brain organizes and interprets sensory information.

7. Ambiguous Figure Colored surface can be either the outside front surface or the inside back surface Cannot simultaneously be both Brain can interpret the ambiguous cues two different ways

8. The Riddle of Separate Sensations Sense receptors Specialized cells that convert physical energy in the environment or the body to electrical energy that can be transmitted as nerve impulses to the brain.

9. Sensation & Perception Processes

10. Measuring Senses Absolute threshold Difference threshold

11. Absolute Threshold The smallest quantity of physical energy that can be reliably detected by an observer.

12. Absolute Sensory Thresholds Vision: A single candle flame from 30 miles on a dark, clear night Hearing: The tick of a watch from 20 feet in total quiet Smell: 1 drop of perfume in a 6-room apartment Touch: The wing of a bee on your cheek, dropped from 1 cm Taste: 1 tsp. Sugar in 2 gal. water

13. Difference Threshold The smallest difference in stimulation that can be reliably detected by an observer when two stimuli are compared;

14. Sensory Adaptation and Deprivation Adaptation The reduction or disappearance of sensory responsiveness when stimulation is unchanging or repetitious. Prevents us from having to continuously respond to unimportant information. Deprivation The absence of normal levels of sensory stimulation.

15. Sensory Overload Overstimulation of the senses. Can use selective attention to reduce sensory overload. Selective attention The focusing of attention on selected aspects of the environment and the blocking out of others.

16. Section 2

17. Vision What we see An eye on the world Constructing the visual world

18. What We See Hue Visual experience specified by colour names and related to the wavelength of light. Brightness Lightness and luminance; the visual experience related to the amount of light emitted from or reflected by an object. Saturation Vividness or purity of colour; the visual experience related to the complexity of light waves.

19. What We See Hue Brightness Saturation

20. An Eye on the World Cornea Protects eye and bends light toward lens. Lens Focuses on objects by changing shape. Iris Controls amount of light that gets into eye. Pupil Widens or dilates to let in more light.

21. An Eye on the World Retina Neural tissue lining the back of the eyeball’s interior, which contains the receptors for vision. Rods Visual receptors that respond to dim light. Cones Visual receptors involved in colour vision. Most humans have 3 types of cones.

22. Afterimages

23. Test of Colour Deficiency

24. Constructing the Visual World Form perception Depth and distance perception Visual constancies: When seeing is believing Visual illusions: When seeing is misleading

25. Form Perception Gestalt principles describe the brain’s organization of sensory building blocks into meaningful units and patterns.

26. Figure and Ground Proximity Seeing 3 pair of lines in A. Similarity Seeing columns of orange and red dots in B. Continuity Seeing lines that connect 1 to 2 and 3 to 4 in C. Closure Seeing a horse in D.

27. Depth and Distance Perception Binocular Cues: Visual cues to depth or distance that require the use of both eyes. Convergence: Turning inward of the eyes, which occurs when they focus on a nearby object. Retinal Disparity: The slight difference in lateral separation between two objects as seen by the left eye and the right eye.

28. Depth and Distance Perception Monocular Cues: Visual cues to depth or distance that can be used by one eye alone.

29. The Ames Room A specially-built room that makes people seem to change size as they move around in it The room is not a rectangle, as viewers assume it is A single peephole prevents using binocular depth cues

30. Visual Constancies The accurate perception of objects as stable or unchanged despite changes in the sensory patterns they produce. Shape constancy Location constancy Size constancy Brightness constancy Colour constancy

31. Shape Constancy Even though these images cast shadows of different shapes, we still see the quarter as round

32. Visual Illusions Illusions are valuable in understanding perception because they are systematic errors. Illusions provide hints about perceptual strategies. In the Muller-Lyer illusion (above) we tend to perceive the line on the right as slightly longer than the one on the left.

33. The Ponzo Illusion Linear perspective provides context Side lines seem to converge Top line seems farther away But the retinal images of the red lines are equal!

34. Fooling the Eye The cats in (a) are the same size The diagonal lines in (b) are parallel You can create a “floating fingertip frankfurter” by holding hands as shown, 5-10” in front of face.

36. Section 3 hearing

37. Hearing What we hear An ear on the world Constructing the auditory world

38. What We Hear Loudness The dimension of auditory experience related to the intensity of a pressure wave. Pitch The dimension of auditory experience related to the frequency of a pressure wave. Timbre (pronounced “TAM-bur”) The distinguishing quality of sound; the dimension of auditory experience related to the complexity of the pressure wave.

39. An Ear on the World

40. Auditory Localization Sounds from different directions are not identical as they arrive at left and right ears Loudness Timing Phase The brain calculates a sound’s location by using these differences.

41. Section 4 Other senses

42. Other Senses Taste: savory sensations Smell: The sense of scents Senses of the skin The environment within

43. The Taste Buds 1. Bitter 2. Sour 3. Sweet 4. Salty

44. Taste: Savoury Sensations Papillae Knoblike elevations on the tongue, containing the taste buds (Singular: papilla). Taste buds Nests of taste-receptor cells.

45. Taste Buds Photograph of tongue surface (top), magnified 75 times. 10,000 taste buds line the tongue and mouth. Taste receptors are down inside the “bud” Children have more taste buds than adults.

46. Four Tastes Four basic tastes Salty, sour, bitter and sweet. Different people have different tastes based on: Genetics Culture Learning Food attractiveness

47. Sense of smell

48. Smell: The Sense of Scents Airborne chemical molecules enter the nose and circulate through the nasal cavity. Vapors can also enter through the mouth and pass into nasal cavity. Receptors on the roof of the nasal cavity detect these molecules.

49. Olfactory System

50. Sensitivity to Touch

51. The Environment Within Kinesthesis The sense of body position and movement of body parts; also called kinesthesia. Equilibrium The sense of balance. Semicircular Canals Sense organs in the inner ear, which contribute to equilibrium by responding to rotation of the head.

52. Perceptual Powers: Origins and Influences Inborn abilities Critical periods Psychological and cultural Influences on perception

53. The Visual Cliff Glass surface, with checkerboard underneath at different heights Visual illusion of a cliff Baby can’t fall Mom stands across the gap Babies show increased attention over deep side at age 2 months, but aren’t afraid until about the age they can crawl (Gibson & Walk, 1960)

54. The Visual Cliff

55. Critical Periods If infants miss out on experiences during a crucial period of time, perception will be impaired. When adults who have been blind since birth have vision restored, they may not see well Other senses such has hearing may be influenced similarly.

56. Psychological and Cultural Influences on Perception We are more likely to perceive something when we need it. What we believe can affect what we perceive. Emotions, such as fear, can influence perceptions of sensory information. Expectations based on our previous experiences influence how we perceive the world. Perceptual Set A habitual way of perceiving, based on expectations. All are influenced by our culture.

57. Perceptual Set What you see in the centre figures depends on the order in which you look at the figures: If you scan from the left, see an old woman If you scan from the right, see a woman’s figure

58. Context Effects The same physical stimulus can be interpreted differently We use other cues in the situation to resolve ambiguities Is this the letter B or the number 13?

59. Puzzles of Perception Subliminal Perception

60. Perceiving without awareness visual stimuli can affect your behaviour even when you are unaware that you saw it nonconscious processing also occurs in memory, thinking, and decision making these effects are often small, however, and difficult to demonstrate and work best with simple stimuli

61. Subliminal Perception Perception versus Persuasion there is no empirical research to support popular notions that subliminal persuasion has any effect on a person’s behaviour persuasion works best when messages, in the form of advertising or self-help tapes, are presented above-threshold, or at a supraliminal level