Myers’ PSYCHOLOGY
(6th Ed)
Chapter 5
Sensation
James A. McCubbin, PhD
Clemson University
Worth Publishers
Sensation
 Sensation
 a process by which our sensory
receptors and nervous system receive
and represent stimulus energy
...
Sensation
 Our
sensory
and
perceptual
processes
work
together to
help us
sort out
complex
processes
Sensation
 Bottom-Up Processing
 analysis that begins with the sense receptors
and works up to the brain’s integration o...
Sensation- Basic
Principles
 Psychophysics
 study of the relationship between
physical characteristics of stimuli and
ou...
Sensation-
Thresholds
 Absolute Threshold
 minimum stimulation needed to detect a
particular stimulus 50% of the time
 ...
Sensation-
Thresholds
 Signal Detection Theory
 predicts how and when we detect the presence
of a faint stimulus (signal...
Sensation-
Thresholds
 Subliminal
 When stimuli are
below one’s
absolute
threshold for
conscious
awareness
0
25
50
75
10...
Sensation-
Thresholds
 Weber’s Law- to perceive as different,
two stimuli must differ by a constant
minimum percentage
 ...
Vision- Stabilized
Images on the Retina
Vision
 Transduction
 conversion of one form of energy to
another
 in sensation, transforming of stimulus
energies into...
Vision
 Hue
 dimension of color determined by
wavelength of light
 Intensity
 amount of energy in a wave
determined by...
The spectrum of
electromagnetic
energy
Vision- Physical
Properties of Waves
Short wavelength=high frequency
(bluish colors, high-pitched sounds)
Long wavelength=...
Vision
 Pupil- adjustable opening in the
center of the eye
 Iris- a ring of muscle that forms the
colored portion of the...
Vision
Vision
 Accommodation- the process by which
the eye’s lens changes shape to help
focus near or far objects on the retina
...
Vision
 Acuity- the sharpness of vision
 Nearsightedness- condition in which
nearby objects are seen more clearly than
d...
Vision
 Normal Nearsighted Farsighted
Vision Vision
Retina’s Reaction
to Light- Receptors
 Rods
 peripheral retina
 detect black, white and gray
 twilight or low light
 ...
Retina’s Reaction
to Light
 Optic nerve- nerve that carries neural
impulses from the eye to the brain
 Blind Spot- point...
Vision- Receptors
Receptors in the Human Eye
Cones Rods
Number
Location in
retina
Sensitivity in
dim light
Color sensitive...
Pathways from the Eyes
to the Visual Cortex
Visual Information
Processing
 Feature Detectors
 nerve cells in the
brain that
respond to specific
features
 shape
 a...
How the Brain
Perceives
Illusory Contours
Visual Information
Processing
 Parallel Processing
 simultaneous processing of several
aspects of a problem simultaneous...
Visual Information
Processing
 Trichromatic (three color) Theory
 Young and Helmholtz
 three different retinal color re...
Color-Deficient Vision
 People who suffer
red-green
blindness have
trouble perceiving
the number within
the design
Visual Information
Processing
Opponent-Process Theory- opposing retinal
processes enable color vision
“ON” “OFF”
red green...
Opponent Process-
Afterimage Effect
Visual Information
Processing
 Color Constancy
 Perceiving familiar objects as having
consistent color, even if changing...
Audition
 Audition
 the sense of hearing
 Frequency
 the number of complete wavelengths that
pass a point in a given t...
The Intensity of Some
Common Sounds
Audition- The Ear
 Middle Ear
 chamber between eardrum and cochlea
containing three tiny bones (hammer, anvil,
stirrup) ...
Audition
 Place Theory
 the theory that links the pitch we hear with
the place where the cochlea’s membrane is
stimulate...
How We Locate
Sounds
Audition
 Conduction Hearing Loss
 hearing loss caused by damage to the
mechanical system that conducts sound
waves to t...
Audition
 Older people tend to hear low
frequencies well but suffer hearing loss
for high frequencies
1
time
10
times
100...
Touch
 Skin Sensations
 pressure
 only skin
sensation with
identifiable
receptors
 warmth
 cold
 pain
Pain
 Gate-Control Theory
 theory that the spinal cord contains a
neurological “gate” that blocks pain
signals or allows...
Taste
 Taste Sensations
 sweet
 sour
 salty
 bitter
 Sensory Interaction
 the principle that one sense may influenc...
Smell
Receptor cells in
olfactory membrane
Nasal
passage
Olfactory
bulb
Olfactory
nerve
Age, Sex and Sense
of Smell
Women
Men
10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99
Age Group
4
3
2
0
Number
of co...
Body Position and
Movement
 Kinesthesis
 the system for sensing the position and
movement of individual body parts
 Ves...
5 sensationenhanced (1) (1)
5 sensationenhanced (1) (1)
5 sensationenhanced (1) (1)
5 sensationenhanced (1) (1)
5 sensationenhanced (1) (1)
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  • Complete 5.1 prior to beginning
  • 5.2 Top Picture—to show the difference between sensation and perception. Looks like a meaningless blotch, students will try to figure it out—stimulation/sensation is being received but not perceived. The subject is a dog, and only part of a dog. Students will probably try to see the whole dog; you cannot tell figure from ground 5.2 Bottom picture—Fraser Spiral—it looks like a spiral but is actually a set of concentric circles
  • The Forest Has Eyes is the title of this work---in studying it we look at the expressions on the faces, there is something foreboding about this picture, and after we have read the title we notice other things…
  • Top Down is the involvement of the brain in making meaning out of stimuli. For example there are people who can see everything clearly (sensation) but cannot recognize even their own faces (perception). Placing meaning to sensations and stimuli is the act of perception
  • Three methods to test Method of Limits: begin with a minimal stimulus and increase until it is perceived by subject Method of right and wrong cases: subject sees identical stimuli repeatedly and says yes if perceives them or it they are different, and no if not perceived or the two are not different—informs how likely it is that any given stimulus level or difference between stimuli will be perceived by subject. Method of adjustment—adjust a comparison stimulus until it appears to be identical to the standard stimulus, errors occur and are noted then averaged to give a measure of jnd Try the timer in the kitchen—put it in a quiet room, move away and then move back—the point at which the ticking is perceived is the absolute threshold, at that point they may be able to hear sometimes and others time not, needing to move a few feet one way or the other—lapses of attention, fatigue other factors influence
  • Lay audiences accept the idea of subliminal persuasion but it has not been substantiated in research
  • Try the following experiment: two envelopes, one with two quarters in it, the subject will be able to tell the difference, but then put the envelopes in a pair of shoes and try to tell the difference Weber's Principle: difference thresholds grow with the magnitude of the stimulus If you make $5 p/h a 25 cent hour raise will be noticeable but at $10 p/h you may need 50 cents. If you are in sales, three piece suit and sweater, sell the suit first because after the suit the man will be more likely to buy In car sales, after the sale customer won’t really notice $500 stereo ADAPTation—habituation After drinking tea with lemon, a grapefruit will not taste as sour … but after a roll, it will taste especially sour After holding salty water in mouth, it will taste less salty, and drinking fresh water afterwards, it will taste sweet
  • 5.3—to demonstrate that the eye is always moving 5.3 a—looking at the center will lead to the perception of movement, stare for 30 seconds and then stare at a white surface (wall or paper) , most will see after image of rotary motion 5.3b---stare at black dot in the middle for about 60 seconds and then look at the white dot, even if try to look hard, still will see an image of the grid pattern jiggling on top of the figure due to involuntary eye movements 5.3c—stare at the fuzzy contoured disc on the right, after about 30 seconds the disc will disappear, but this is almost impossible to do with the sharp contoured disc because the fizzy image jiggling on the retina causes only slight changes in the amount of light stimulating the receptors and if eyes are kept still this small change is not enough to maintain perception and disc fades from view. On the sharp one, the slight jiggling of the eyes causes sharp contour to fall first on some receptors and then on others so the amount of light stimulating the receptors is constantly changed and disc remains visible
  • The blind spot occurs is the location in the retina where the visual cortex exits to the brain, there are no receptors there What our brain does, typically, is fill in that missing piece based on what it estimates to be there Blindsight—we can see things we don’t perceive
  • Retinal ganglion cells---go back to 5.3 and then to 5.4 5.4a is the cover of a catalog and students complained of seeing gray spots The grid pattern is called the Hermann grid after the German physiologist who first discovered it The elusive gray spots can be explained in terms of the receptive fields of the retinal ganglion cells Some of the cells are an on center surrounded by an off (like a donut). Light has opposite, antagonistic effects
  • Feature detectors respond to specific features of a scene, edges, lines, angles, movements, and from these the brain assembles the perceived image Illusory Figures 5.6a—just three dots produce a triangle 5.6—the last three on the page highlight the complexity of illusory figures, curved vase, x-mas tree, 3-d pyramid
  • 5.7 is an initial test for color blindness, students with scores above 16 have an 81 percent chance of failing a standard screening for color vision 8 percent of males, .05 percent of females show color weaknesses Color defects are genetically transmitted, recent research has conclusively mapped this transmission Monochromats—have no or only one type of functioning cone type and respond to light like a black and white film—colors are records only as gradations of intensity, likely to find daylight uncomfortable if no functioning cones, those with one cone okay but still can’t discriminate colors—very small number of people have this Dichromats—one malfunctioning cone system, depending on type, various colors will not be perceived, inability to perceive blue is the rarest, in 1950 England, found 17 people
  • 5.9—shows that colors can be subjective, no wavelengths of light Look in the center of this and many people will see wavy patterns of pastel , because the eye is constantly moving and these movements displace the image of the diagonal lines over the retinal receptors and create a pattern of receptor activity that typically occurs from viewing colored stimuli
  • A recent U of Tenn. study found that 60 percent of college students suffer some high-frequency hearing loss Loud music is believed to be the culprit Live concerts—120 + decibels, louder than jack hammer, chainsaw OSHA says that 85 decibels (food processor) 8 hours, 5 days a week will eventually cause permanent hearing loss For each 5 decibel increase, the time it takes to cause lasting injury drops by half Try: hold finger up as if taking a court room oath, rub thumb, finger together and should hear a scrtiching sound---if not, MAY have hearing loss
  • Experiment—have someone sit in front of class with eyes closed. Clap hands around head and ask student to identify where the sound comes from—will be able to do so when the sounds come from one side or the other, but less clearly able to do so when the sounds overhead in back or in front The perceived difference in sounds is related to the time at which the sound is received
  • Ringing in the ears is called tinnitus, affects more than 36 million Americans Most common cause is exposure to loud noises, but also can be caused by certain drugs, ear infections, food allergies In most severe form, this ailment is incapacitating
  • Touch localization demonstration, concentrate on where the sensations of touch are felt: Touch two index fingers together, feel it in both Touch finger to bottom lip, light taps, felt mostly in lip even though both are being stimulated Touch ankle, now its felt mostly in finger Touch localization depends on the relative lengths of the pathways from the stimulated parts to the brain
  • Pain is an important signal to our bodies The experience of pain can be influenced by information from the brain Chronic pain—est. that over 100 million people suffer from this One study had teen age burn patients undergo a few minutes of wound treatment while they played Nintendo or while they were in a virtual reality environment—the patients felt less pain and spent less time thinking about their pain in virtual reality than Nintendo due to concept of “presences”—illusion of going inside another world. Pain requires attention
  • Some taste sensations are genetically programmed, such as sweet, and finding bitter and sour foods unpleasant A study of babies had sweet eliciting smiles, lip smacking, and sour eliciting protrusion of tongue These reactions make good evolutionary sense Animals tend to be neophobic, and human children are reluctant to try new things One experiment asked a group of subjects to taste two groups of food (that were the same). When the items were accurately named (chopped tomatoes, oatmeal, beefsteak) more willing them when given novel names (pendula fruit, lat, langua steak) However, as true with other stimuli , mere exposure makes us like them more
  • Smell can be used to identify gender The phenomenon of women in the same home having the same menstrual cycle is related to smell—researcher Martha McClintock discovered this 30 years ago while at Wellesley College; now a researcher at the U of Chicago found that smell can stimulate ovulation Citrus odors make people more alert, spiced apple helps relaxation Pumping certain pleasant food odors cut by 40 percent shoving, pushing in New York subways People in New York mall were more likely to help strangers when there was the aroma of roasting coffee or baking cookies Good and Plenty licorice combined with cucumber increased female blood flow by 14 percent (anything over 10 percent was considered stimulating), baby talc 13 percent, lavender + pumpkin pie 11 percent Cherry cut flow by 18 percent, charcoal barbecue 15 percent, men’s cologne by 1 percent Women seem to be excited by things that remind them of childhood, or are fresh smelling, relating to safety and security needed in order to feel sexual
  • Ian Waterman, after viral infection, lost his sense of light touch and body position and movement—can walk but must look at limbs to direct them When lights go out, he falls and cannot get up again until they come back on When he is not looking at his body, he moves very little, unlike most of us who move around quite a bit Synesthesia—sensory condition in which stimulating one modality leads to perception in another (to perceive together) 1 in 2,000 occurrence, females outnumber 6 to 1, seems to run in families so there may be a genetic base
  • 5 sensationenhanced (1) (1)

    1. 1. Myers’ PSYCHOLOGY (6th Ed) Chapter 5 Sensation James A. McCubbin, PhD Clemson University Worth Publishers
    2. 2. Sensation  Sensation  a process by which our sensory receptors and nervous system receive and represent stimulus energy  Perception  a process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events
    3. 3. Sensation  Our sensory and perceptual processes work together to help us sort out complex processes
    4. 4. Sensation  Bottom-Up Processing  analysis that begins with the sense receptors and works up to the brain’s integration of sensory information  Top-Down Processing  information processing guided by higher-level mental processes  as when we construct perceptions drawing on our experience and expectations
    5. 5. Sensation- Basic Principles  Psychophysics  study of the relationship between physical characteristics of stimuli and our psychological experience of them  Light- brightness  Sound- volume  Pressure- weight  Taste- sweetness
    6. 6. Sensation- Thresholds  Absolute Threshold  minimum stimulation needed to detect a particular stimulus 50% of the time  Difference Threshold  minimum difference between two stimuli required for detection 50% of the time  just noticeable difference (JND)
    7. 7. Sensation- Thresholds  Signal Detection Theory  predicts how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise)  assumes that there is no single absolute threshold  detection depends partly on person’s  experience  expectations  motivation  level of fatigue
    8. 8. Sensation- Thresholds  Subliminal  When stimuli are below one’s absolute threshold for conscious awareness 0 25 50 75 100 Low Absolute threshold Medium Intensity of stimulus Percentage of correct detections Subliminal stimuli
    9. 9. Sensation- Thresholds  Weber’s Law- to perceive as different, two stimuli must differ by a constant minimum percentage  light intensity- 8%  weight- 2%  tone frequency- 0.3%  Sensory adaptation- diminished sensitivity as a consequence of constant stimulation
    10. 10. Vision- Stabilized Images on the Retina
    11. 11. Vision  Transduction  conversion of one form of energy to another  in sensation, transforming of stimulus energies into neural impulses  Wavelength  the distance from the peak of one wave to the peak of the next
    12. 12. Vision  Hue  dimension of color determined by wavelength of light  Intensity  amount of energy in a wave determined by amplitude  brightness  loudness
    13. 13. The spectrum of electromagnetic energy
    14. 14. 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)
    15. 15. Vision  Pupil- adjustable opening in the center of the eye  Iris- a ring of muscle that forms the colored portion of the eye around the pupil and controls the size of the pupil opening  Lens- transparent structure behind pupil that changes shape to focus images on the retina
    16. 16. Vision
    17. 17. Vision  Accommodation- the process by which the eye’s lens changes shape to help focus near or far objects on the retina  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
    18. 18. Vision  Acuity- the sharpness of vision  Nearsightedness- condition in which nearby objects are seen more clearly than distant objects because distant objects in front of retina  Farsightedness- condition in which faraway objects are seen more clearly than near objects because the image of near objects is focused behind retina
    19. 19. Vision  Normal Nearsighted Farsighted Vision Vision
    20. 20. Retina’s Reaction to Light- Receptors  Rods  peripheral retina  detect black, white and gray  twilight or low light  Cones  near center of retina  fine detail and color vision  daylight or well-lit conditions
    21. 21. Retina’s Reaction to Light  Optic nerve- nerve that carries neural impulses from the eye to the brain  Blind Spot- point at which the optic nerve leaves the eye, creating a “blind spot” because there are no receptor cells located there  Fovea- central point in the retina, around which the eye’s cones cluster
    22. 22. 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
    23. 23. Pathways from the Eyes to the Visual Cortex
    24. 24. Visual Information Processing  Feature Detectors  nerve cells in the brain that respond to specific features  shape  angle  movement Stimulus Cell’s responses
    25. 25. How the Brain Perceives
    26. 26. Illusory Contours
    27. 27. Visual Information Processing  Parallel Processing  simultaneous processing of several aspects of a problem simultaneously
    28. 28. Visual Information Processing  Trichromatic (three color) Theory  Young and Helmholtz  three different retinal color receptors  red  green  blue
    29. 29. Color-Deficient Vision  People who suffer red-green blindness have trouble perceiving the number within the design
    30. 30. Visual Information Processing Opponent-Process Theory- opposing retinal processes enable color vision “ON” “OFF” red green green red blue yellow yellow blue black white white black
    31. 31. Opponent Process- Afterimage Effect
    32. 32. Visual Information Processing  Color Constancy  Perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object
    33. 33. Audition  Audition  the sense of hearing  Frequency  the number of complete wavelengths that pass a point in a given time  Pitch  a tone’s highness or lowness  depends on frequency
    34. 34. The Intensity of Some Common Sounds
    35. 35. Audition- The Ear  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, contining the cochlea, semicurcular canals, and vestibular sacs  Cochlea  coiled, bony, fluid-filled tube in the inner ear through which
    36. 36. Audition  Place Theory  the theory that links the pitch we hear with the place where the cochlea’s membrane is stimulated  Frequency Theory  the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch
    37. 37. How We Locate Sounds
    38. 38. Audition  Conduction Hearing Loss  hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea  Nerve Hearing Loss  hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerve
    39. 39. Audition  Older people tend to hear low frequencies well but suffer hearing loss for high frequencies 1 time 10 times 100 times 1000 times 32 64 128 256 512 1024 2048 4096 8192 16384 Frequency of tone in waves per second Low Pitch High Amplitude required for perception relative to 20-29 year-old group
    40. 40. Touch  Skin Sensations  pressure  only skin sensation with identifiable receptors  warmth  cold  pain
    41. 41. Pain  Gate-Control Theory  theory that the spinal cord contains a neurological “gate” that blocks pain signals or allows them to pass on to the brain  “gate” opened by the activity of pain signals traveling up small nerve fibers  “gate” closed by activity in larger fibers or by information coming from the brain
    42. 42. Taste  Taste Sensations  sweet  sour  salty  bitter  Sensory Interaction  the principle that one sense may influence another  as when the smell of food influences its taste
    43. 43. Smell Receptor cells in olfactory membrane Nasal passage Olfactory bulb Olfactory nerve
    44. 44. Age, Sex and Sense of Smell Women Men 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99 Age Group 4 3 2 0 Number of correct answers Women and young adults have best sense of smell
    45. 45. Body Position and Movement  Kinesthesis  the system for sensing the position and movement of individual body parts  Vestibular Sense  the sense of body movement and position  including the sense of balance
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