Presentation is loading. Please wait.

Presentation is loading. Please wait.

Myers’ PSYCHOLOGY Chapter 5 Sensation Complete 5.1 prior to beginning.

Similar presentations


Presentation on theme: "Myers’ PSYCHOLOGY Chapter 5 Sensation Complete 5.1 prior to beginning."— Presentation transcript:

1 Myers’ PSYCHOLOGY Chapter 5 Sensation Complete 5.1 prior to beginning

2 Sensation and Perception
a process by which our sensory receptors and nervous system receive and interpret stimulus energy After receiving sensory information we must process it and this is perception Perception a process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events Sensation and perception blend into one continuous process 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

3 Sensation Bottom-Up Processing Top-Down Processing
analysis that begins with the sense receptors and works up to the brain’s integration of sensory information Detects lines, angles, and colors Top-Down Processing information processing guided by higher-level mental processes as when we construct perceptions drawing on our experience and expectations Information not form our senses, knowledge based Interpretation 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

4 The Forest Has Eyes Our sensory and perceptual processes work together to help us sort out complex processes Bottom-up is the colors, lines, angles of the horses, rider and sourroundings Top-down is the title of the painting and what will give the painting meaning 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…

5 Sensation and Perception Cycle

6 Thresholds We live in a world on constant stimuli
What do we notice and not notice? What do we feel and not feel? What do we sense and perceive? Psychophysics if the study of how physical energy relates to our psychological experience What stimuli can we detect? At what intensity? How sensitive are we to changing stimulation

7 Psychophysics Psychophysics
study of the relationship between physical characteristics of stimuli and our psychological experience of them Light- brightness Sound- volume Pressure- weight Taste- sweetness

8 Sensation- Thresholds
Absolute Threshold What we are super-sensitive too, even if the stimuli is faint Eyelash on our face is one example Absolute threshold is the minimum stimulation needed to detect a particular stimulus 50% of the time 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

9 Signal Detection Theory
Detecting a weak stimuli depends on the signal’s strength but also on a psychological state predicts how and when we detect a weak stimulus signal Measured as ratio of “hits” to “false alarms” Why do people respond differently to same stimuli Why does same person’s reactions vary by circumstances? Why parents hear the slightest sound fro their baby, but miss louder sounds from other sources Detection depends partly on person’s experience expectations motivation level of fatigue

10 Subliminal! We have all heard of this
Subliminal messages can be both visual and auditory Subliminal means stimuli below our threshold that we unconsciously detect and perceive Remember that absolute threshold is 50% of the time – so yes we can be and are stimulated by things below that threshold Can we feel what we do not know and cannot describe? Can we be manipulated using this? Psychologists say NO! When it appears that they do is it placebo effect?

11 Sensation- Thresholds
25 50 75 100 Low Absolute threshold Medium Intensity of stimulus Percentage of correct detections Subliminal stimuli Subliminal When stimuli are below one’s absolute threshold for conscious awareness Lay audiences accept the idea of subliminal persuasion but it has not been substantiated in research

12 Sensation - Thresholds
Difference Threshold (aka JND – just noticeable difference) minimum difference between two stimuli required for detection 50% of the time Increases with the magnitude of the stimulus Weber’s Law- to be perceived as different, two stimuli must differ by a constant minimum percentage Stimuli must differ by a constant proportion not amount to be noticed light intensity- 8% difference weight- 2% difference tone frequency- 0.3% difference 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

13 Sensory Adaptation Diminished sensitivity as a consequence of constant stimulation Example – you walk into a house and it smells, but an hour later you no longer notice the smell. You get used to it – you adapt Diminishing sensitivity to unchanging stimulus

14 End Day 1

15 Day 2 – Backmasking and Subliminal Clips and Discussion
Play several clips on subliminal messages and backmasking Response: Students are to write a 2 paragraph response analyzing what they saw today (combined with Internet Research) and explain if subliminal and backmasking work.

16 Subliminal Commercials

17 End Day 2

18 Vision Amazing – how does light become images? Transduction
conversion of one form of energy to another Stimulus energy becomes neural messages Stimulus input is light energy Not color that strikes the eyes, but electromagnetic energy that our visual system perceives as color We se only a mall part of the color spectrum 2 parts of light help our sensory experience: 1. Wavelength - the distance from the peak of one wave to the peak of the next Determines hue (color we experience) 2. Intensity – Amount of energy in the light waves Influences brightness

19 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)

20 The Eye Light enters the eye through the cornea
Light bends to provide focus Light then passes through the pupil Pupil is an adjustable opening in the center of the eye Pupil is regulated by the iris Iris- a ring of muscle that forms the colored portion of the eye around the pupil and controls the size of the pupil opening Adjusts light intake by dilating/constricting in response to intensity or even inner emotions Behind the pupil is the lens

21 The Eye Continued Lens focuses the incoming rays into an image on the eye’s light sensitive back surface Does this through the process of accommodation – changing the curvature Retina contains the receptor rods and cones and layers of neurons that process the visual information Rods – detect black, white and grey/peripheral and twilight vision Cones – function in daylight and well-lit conditions/fine detail/color sensations Fovea is the retina’s central area of focus add where cones cluster around Fovea has cones but no rods

22 Vision

23 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

24 Vision Acuity – sharpness of vision Nearsightedness Farsightedness
Can be changed by slight variations in the shape of the eye Nearsightedness Light rays from distant objects focus in the front of the retina Condition in which nearby objects are seen more clearly than distant objects Farsightedness The image of near objects is focused behind retina Condition in which faraway objects are seen more clearly than near objects

25 Vision Normal Nearsighted Farsighted Vision Vision Vision

26 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

27 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

28 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

29 Pathways from the Eyes to the Visual Cortex

30 Day 4 – Vision in more detail
KQLW Chart Complete 1st 2 columns What I already know/learned Questions I have still Watch videos (also on website for class) G:\Eye\030 How Eyes Work - An Introduction.mp4 Start at 1:00 into the video G:\Eye\032 Visual Processing in the Retina.mp4 Start at 4:00 minutes into video Complete column 3 What I learned today Complete column 4 What I still want to learn

31 Start Day 5

32 Visual Information Processing
Visual information goes from the retina in the eye to the thalamus then to the brain’s visual cortex in the occipital lobe 130 million rods and cones in the retina Transmitted by the ganglion cells Ganglions’ axons make up the optic nerve Retinal cells are VERY sensitive Can misfire Even pressure can trigger misfires Brain interprets the misfires as light

33 Feature Detection Ganglion cells send signals to the visual cortex
Feature detector neurons respond to a scene’s specific features Edges, lines, angles and movements Visual cortex passes information to other areas of the cortex that respond to more complex patterns

34

35 “Vast Visual Encyclopedia”
Cells that are distributed throughout the brain Respond to one stimulus but not another Called supercells Fire only when cues trigger them too Ex: A goalie blocking a shot when they see the ball or puck coming or anticipate the direction it might come from

36 How the Brain Perceives
Perception combines sensory input with assumptions and expectations If you stare at the Necker cube, it changes every few seconds This demonstrates that perception is shifting Brain constructs varying perceptions

37 Parallel Processing Our brains process several things at once
Divides visual scene into dimensions Color, depth, movement, and form Our perceptions are based on integration of all from all the processing that happened simultaneously Different areas of the brain process each part of the visual scene Damage one area and certain parts of vision do not work i.e. pouring a drink into a class – appears “frozen” – can’t see movement

38 Parallel Processing…

39 Summary of Processing of Visual Information

40 Color Vision Light rays are NOT colored
Color is in our brains – not in the object we see The brain manufactures color Theory is that any color can be created by combining light waves of 3 colors Red, green, and blue Retina only has 3 color receptors

41 Color-Deficient Vision
People who suffer red-green blindness have trouble perceiving the number within the design They have only 2 color receptors 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

42 Opponent-Process Theory
After leaving receptor cells, visual info is analyzed in terms of if the opponent colors Neurons are turned on and off by certain colors “ON” “OFF” red green green red blue yellow yellow blue black white white black 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

43 Opponent Process- Afterimage Effect
We get tired of our green response by staring at green So – when we stare at the white (which contains all colors), we see only the red part of the red-green pairing

44 Color Constancy Perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object In English – we see common objects as the same color even though the wavelengths may actually change.

45 End Day 5

46 Audition Audition Frequency Pitch the sense of hearing
the number of complete wavelengths that pass a point in a given time Pitch a tone’s highness or lowness depends on frequency

47 The Intensity of Some Common Sounds
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

48

49 Audition- The Ear Middle Ear Inner Ear Cochlea
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

50 Audition Place Theory Frequency 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

51 How We Locate Sounds 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

52 Audition Conduction Hearing Loss Nerve 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 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

53 Audition Older people tend to hear low frequencies well but suffer hearing loss for high frequencies 1 time 10 times 100 1000 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

54 Touch Skin Sensations pressure warmth cold pain
only skin sensation with identifiable receptors warmth cold pain 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

55 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 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

56 Taste Taste Sensations Sensory Interaction sweet sour salty bitter
the principle that one sense may influence another as when the smell of food influences its taste 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

57 Smell nerve Olfactory bulb Receptor cells in Nasal olfactory membrane
passage Olfactory bulb nerve

58 Age, Sex and Sense of Smell
Women Men Age Group 4 3 2 Number of correct answers Women and young adults have best sense of smell 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

59 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 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


Download ppt "Myers’ PSYCHOLOGY Chapter 5 Sensation Complete 5.1 prior to beginning."

Similar presentations


Ads by Google