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How do you make decisions about the world around you?

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Presentation on theme: "How do you make decisions about the world around you?"— Presentation transcript:

1 How do you make decisions about the world around you?

2 Stimuli What is the information OUTSIDE your body called? Stimuli include: light sound heat pressure chemical

3 Sensation What is it called when the stimuli are detected and transferred? (A physical reaction within the body in response to an external stimuli)

4 Perception Sensation + Past Experience = (The organization of sensation into meaningful information)

5 Sensation is to perception as________ is to ___________ A. Interpretation; organization B. Transmission; interpretation C. Integration; interpretation D. Adaptation; interpretation

6 Sensation is to perception as________ is to ___________ A. Interpretation; organization B. Transmission; interpretation C. Integration; interpretation D. Adaptation; interpretation

7 Do we detect every stimulus in our environment? No, it has to be strong enough for us to detect. We have a sensory threshold. Two types of sensory thresholds. - Absolute threshold - Difference threshold

8 Absolute threshold The smallest possible strength of a stimulus that can be detected half the time.






14 Difference Threshold (Just Noticeable Difference) the smallest possible change in a stimulus that can be detected half the time. True OR false? ……. Our sensory experiences depend more on changes than the absolute size of the stimulus.

15 Difference Threshold (Just Noticeable Difference) True Sensory experiences depend more on changes than the absolute size of the stimulus.

16 Difference Threshold (Just Noticeable Difference) Example – What do you notice more? 3# brick into an empty backpack? OR 3# brick into a 100# backpack ?

17 Web e rs law The larger or stronger a stimulus, the larger the amount of change re q uired for an observer to notice a diff e rence. Doubling sweetness takes 3x the sugar 2x the light < doubly bright

18 Sensory Adaptation -Our sensory receptor cells become less responsive to a constant stimulus. -This allows us to quickly notice new or changing stimuli.

19 Sensory Adaptation Give me an example: Movie theater lighting pressure of your clothes hot / cold (esp. water) Odors in a lab Street noise (background)

20 Sensory Adaptation (p. 212)

21 Signal Detection Theory Studies the relationship between: Motivation, Sensitivity &, Decision Making Different thresholds depending on the circumstances (importance of the detection matters) Radar operator looking for a blip Expecting to see someone at a party

22 THE SENSES Vision Hearing Smell Taste Touch Vestibular Kinesthetic

23 VISION Light waves….rods & cones in eyes Controlled by Occipital lobe Vision involves changing light energy into energy of the nervous system.






29 Rods and Cones RODS Require little light to function…… useful in night vision. Not sensitive to color.

30 Rods and cones CONES Sensitive to color Require more light than rods…… useful for daytime vision. Study tip: cones = color…..both start w/ c.

31 Retinal disparity - The difference between the two images on the retina. Binocular fusion - The combining of the two images that the eyes receive.

32 Hearing

33 Sound waves move hairs in Ears Controlled by: upper temporal area of cerebral cortex Ear bones convert vibrations into signal


35 Taste Soluble substances on taste buds of the Tongue Controlled by: Cerebral cortex (temporal lobe) What is the Stimulus? Chemical molecules


37 Mr. Tongue

38 Smell Volatile substances contact hair cells in nose Controlled by: olfactory bulb (front temporal) Olfactory nerve one of the longest in the body….1 synapse on the way to the brain!

39 Smell

40 Touch Pressure, warmth, cold and pain receptors in the skin Controlled by: parietal lobe headband Sensitivity to pressure varies from place to place in the skin. (Mr. Homunculus & p 235)


42 Vestibular Mechanical / gravitational forces operate on inner ear Controlled by: cerebellum & parietal lobe Regulates the bodys sense of balance by sending messages from semicircular canal fluid to brain.



45 Kinesthetic Body movements w/in muscles/joints/tendons Controlled by: cerebellum & cerebral cortex (esp. parietal) Senses movement and position of body parts

46 Kinesthetic: How does it work? Sensory neurons located in the joints and muscles communicate information to the brain about changes in body position. Maintain posture & balance

47 Gestalt The perception of stimuli as wholesrather than bits and pieces.

48 x x x x x oo X x x xx

49 x x x x oo X x xx

50 Three Gestalt principles Closure Proximity Similarity

51 Closure Tendency to group according to enclosed or completed figures rather than open or incomplete parts.

52 Closure


54 Proximity Tendency to group together objects that are close to each other.

55 Proximity 3 columns3 Rows

56 Similarity Tendency to group elements together that are similar to one another.

57 Similarity ColumnsRows

58 Figure and Ground One form of perceptual organization in which we distinguish between an object and its background.

59 Figure and ground Vase or face?

60 stalt.swf stalt.swf

61 Perceptual inference Perception based on sensory input and past experience. Mostly automatic & unconscious Fill in the gaps of what you sense!

62 Perceptual inference Auditory – hear a bark & assume its your dog Visual – driving over a hill, you ASSUME the road continues

63 We learn to perceive Learned – babies learn to recognize faces Interaction with our environment is necessary for the development of perception. (Kitten example) Influenced by -needs -beliefs -expectations Cant just RIDE in the car…….you must DRIVE!

64 We learn to perceive Perceptual Set- You tend to believe/see what you expect heuristics lead to pre-judging (mis-judging) racism

65 External (monocular) cues Interposition Light & Shadow Relative height Texture-density Linear Aerial & Atmosphere Motion parallax Relative Motion

66 Relative Height: Farther objects appear smaller


68 Interposition: Whole object closer than partial

69 Shadows: attached or cast? Give position clues



72 Texture –Density: Near objects = more detail

73 Texture –Density: Far objects = less detail

74 Aerial & Atmospheric: Bluing-far looks blue graying – pollution helps

75 Aerial & Atmospheric: Bluing-far looks blue graying – pollution helps

76 Aerial & Atmospheric: Bluing-far looks blue

77 Motion parallax As you move, NEAR objects seem to move more than FAR objects cars on a highway objects in a straight line of sight

78 Linear Perspective: parallel lines meet in distance

79 Linear Perspective

80 Accommodation The thickening or thinning of the lens to focus on objects near or far. Thickens for near objects. Thins for distant objects.


82 Relative motion If you look near, far things move with you. If you look far, near things move in the opposite direction. Look out your car window!

83 Relative motion

84 Internal / Binocular cues Convergence Retinal disparity

85 Convergence Eyes turn inward to look at an object. As the eyes turn inward, the muscles of the eyes send messages to the brain telling it the object is near.

86 Retinal Disparity / Binocular Fusion The two eyes see different images, the brain recognizes this, and then calculates distance. The two images are fused into one, creating one large, coherent image in your brain.

87 Constancy The tendency to perceive certain objects in the same even though light, angle, or distance may change. Size/distance Shape/angle Brightness/color 3 Types

88 Size constancy: all the same size but pilots know this better than you!

89 Shape constancy Perceive the shape of a known object as remaining unchanged although we may perceive it from different angles (different images cast on our retina)

90 Brightness constancy Perceive the brightness of an object as stable or unchanging regardless of a change in lighting. Objects in sunlight & shade

91 Illusions Illusions occur when we misperceive the true characteristics or properties of an object.

92 Illusions Spatial summation – A collection of individuals = a different whole

93 Sunday Afternoon on the Island of Grand Jatte by Georges Seurat ( )

94 Does our mind always accurately represent reality? -Ames room (p. 231)

95 Muller-Lyer Illusion


97 S ubliminal P erception subliminal means literally below the threshold movie theater experiment -subsequent experiments do NOT support this! -There IS evidence that we can detect subliminal information -Word Recognition experiment -Explanation for déjà vu?

98 E xtra S ensory P erception Receiving info. From channels other than the normal senses -Clairvoyance: perception w/o sensory input -Telepathy: mind reading / thought transference -Psychokinesis: moving objects w/mind -Precognition: foretelling of events

99 E xtra S ensory P erception - Ms. Cleo - 6th Sense - Yuri Geller - Spoon Bending - John Edward - The Amazing Randi million $ challenge

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