Unit 3: Sensation and Perception

CHAPTER

3Sensation and Perception

Quote of the week: One’s perception is one’s reality.

Copyright ©Pearson Education 2013


Enduring Issues

To what extent do our perceptual experiences accurately reflect what is in the outside world? Diversity-

UniversalityDiversity-

Universality

Stability-ChangeStability-Change

Mind-BodyMind-Body

Nature-NurtureNature-Nurture

Person-SituationPerson-Situation



Enduring Issues

In what ways do our experiences of the outside world change as a result of experience over the course of our lives?

Diversity-UniversalityDiversity-

Universality


Mind-BodyMind-Body





Enduring Issues

To what extent do people around the world perceive events in the same way?


Universality


Mind-BodyMind-Body





Enduring Issues

In what ways do our experiences depend on biological processes?


Universality


Mind-BodyMind-Body



The Nature of Sensation



e n s a t i o ne n s a t i o n

The experience of

sensory stimulation



• Difference threshold: Smallest change in stimulation that can be detected 50% of the time

• Absolute threshold: Least amount of energy that can be detected as a stimulation 50% of the time

LEARNING OBJECTIVE: Explain the difference between absolute and differencethresholds and the effect of adaptation on sensory thresholds. Summarize the evidence for subliminal perception and extrasensory perception.

Sensory Thresholds



Adaptation

Adaptation:An adjustment of the senses to the level of stimulation they are receiving



Subliminal Perception

Subliminal stimuli: Stimuli below the level of conscious awareness

Vision



LEARNING OBJECTIVE: Describe the role of rods, cones, bipolar cells, ganglion cells, the optic nerve, the optic chiasm, and feature detectors in the brain in causing a visual experience.

The Visual System

Images adapted from LivePsych by Pearson, Inc.

Light enters the eye through the cornea.

It passes through the pupil, and is focused by the lens onto the retina.

http://www.prenhall.com/livepsych/



The Receptor Cells

• Cones located in fovea– Day vision (color)

• Rods in periphery– Night vision

(light and dark)



The Receptor Cells



Dark adaptation:Increased sensitivity of rods and cones in darkness

Our eyes adjust to different levels of stimulation based on changes in the sensitivity of rods and cones.

Adaptation

Light adaptation:Decreased sensitivity

of rods and cones in bright light

LEARNING OBJECTIVE: Explain how dark and light adaptation affect our vision and how they cause afterimages.LEARNING OBJECTIVE: Explain how dark and light adaptation affect our vision and how they cause afterimages.

Afterimage“The gray-and-white afterimage (in the figure at right) appears because the part of the retina that is exposed to the dark stripes of the upper square becomes more sensitive (dark adapted). The area exposed to the white part of the upper square becomes less sensitive (light adapted). When you shift your eyes to the lower square, the less sensitive parts of the retina produce the sensation of gray rather than white. The afterimage fades within a minute as the retina adapts again, this time to the solid white square.”

– Page 88 (Morris & Maisto)



From Eye to Brain

1. Rods and cones are connected to bipolar cells.

2. Bipolar cells hook up with ganglion cells.

3. Axons of ganglion cells join to form optic nerve, which carries messages to the brain.





Beau: Optical Illusions



Color Vision

LEARNING OBJECTIVE: Distinguish between hue, saturation, brightness, additive and subtractive color mixing. Explain the two major theories of color perception.

Hues:Aspects of color that correspond to names such as red, green, and blue

Saturation:The vividness or richness of a hue

Brightness:The nearness of a color to white as opposed to black

Increasing saturation

Increasing saturation

Increasing brightnessIncreasing brightness



Neil Harbisson: Hearing Color

Hearing



Sound

Frequency – hertz (Hz): waves (cycles) per second

• Pitch– High– Low

LEARNING OBJECTIVE: Explain the characteristics of sound waves and their effect on the sensation we call sound.



Sound

Amplitude: decibelsVolume

– soft to loud




LEARNING OBJECTIVE: Describe the path that information about sound travels from the ears to the brain. Explain place theory, frequency theory, and the volley principle.

The Ear




Deafness• Approx. 28 million Americans: Some

form of hearing loss

• Treatments: Hearing aids, surgery, cochlear implants

Tinnitus • Steady, high-pitched hum

• Affects approx. 1 of 8 persons

• Treatments: Drug therapies, “white noise” implants, biofeedback

Hearing Disorders

LEARNING OBJECTIVE: Explain the two major kinds of hearing disorders (deafness and tinnitus).

The Other Senses



LEARNING OBJECTIVE: Describe how stimuli give rise to smells and tastes.

Smell

Source: Human Anatomy and Physiology by Anthony J. Gaudin and Kenneth C. Jones. Copyright © 1989. Reprinted by permission.



Taste



LEARNING OBJECTIVE: Distinguish between the kinesthetic and vestibular senses.

Muscle movement

Posture

Strain on muscles, joints

Equilibrium and body position in space

Kinesthetic and Vestibular Senses



The skin’s nerve receptors send nerve fibers to the brain by two routes:

LEARNING OBJECTIVE: Explain how sensory messages are sent from the skin to the brain. Summarize the sources of differences among people in the degree of pain they experience.

• medulla, thalamus sensory cortex

• thalamus reticular formation

The Skin Sense



Pain

social

Bio psychoBiopsychosocial

Theory

Perception



The brain’s interpretation

of sensory information so

as to give it meaning

e r c e p t i o ne r c e p t i o n



Based on the idea that people have a natural tendency to force patterns onto whatever they

see

LEARNING OBJECTIVE: Distinguish between sensation and perception. Explain the Gestalt principles of perceptual organization. Describe the several perceptual constancies.



Figure Ground Proximity Similarity

Closure Continuity

Perceptual Organization: Gestalt PrinciplesPerceptual Organization: Gestalt Principles


Closure Continuity

Perceptual Organization: Gestalt Principles


Closure Continuity



Closure Continuity



Closure Continuity

Perceptual Organization: Gestalt PrinciplesPerceptual Organization: Gestalt Principles

Perceptual Constancies“Perceptual constancy refers to the tendency to perceive objects as relatively stable and unchanging despite changing sensory information. Once we have formed a stable perception of an object, we can recognize it from almost any position, at almost any distance, under almost any illumination. A house looks like a house day or night and from any angle.”

– Page 110 (Morris & Maisto)



Other Rules of Perception

- Experience plays into perception.

- Memory plays into perception.

- Expectation plays into perception.

- We judge distance and depth.

- How is movement perceived?



Perception of Movement

Real movement:Physical displacement of an object from one position to another

Apparent movement:Perception of movement in objects that are actually standing still

–Autokinetic illusion–Stroboscopic motion–Phi phenomenon



Visual Illusions

Perceptual illusions:Stimulus contains misleading cues that give rise to inaccurate or impossible perceptions

LEARNING OBJECTIVE: Explain how visual illusions arise.



Motivation and emotionMotivation and emotion

ValuesValues

ExpectationsExpectations

Cognitive styleCognitive style

Experience and cultureExperience and culture

PersonalityPersonality

LEARNING OBJECTIVE: Describe how observer characteristics and culture can influence perception.

Observer Characteristics

11

22

33

44

55

66



Other Impacts on Your Perception: Attention



Other Impacts on Your Perception: Perspective



Quote of the week: One’s perception is one’s reality.

“Smell and vision are just two of the senses giving us a window on the

world… [all] combine in a rich mosaic of awareness forming the basis of

consciousness. It is sensation that gives us connections both to our own

selves and to our surroundings” (Morris & Maisto, 2013, p. 81).

Optional Activities

When we look at the world around us, how much are we really seeing? Let’s find out.

On the following slide you will be shown two images flashing alternately. The images are identical except for one major change. See if you can spot the change before time runs out. Then try this again with another set of images.

Image #1(Click anywhere to begin)

CONTINUETRY AGAIN

Image #2(Click anywhere to begin)

CONTINUETRY AGAIN

These slides illustrate that human beings are able to pay attention to only part of the visual sensations that they are exposed to on a moment-by-moment basis. These are the parts that are remembered. This demonstration reminds us that the road between sensation and perception has many twists and turns.

The Blind Spot

Draw two small circles (about six inches apart) on your paper. Hold the paper out in front of you. Close your right eye and stare at the right dot with your left eye. Slowly bring the paper closer to your face. As you do this, the left dot will disappear.

After Images

Visual sensations that persist after the initial stimulus has been removed are called “afterimages.”

On the next slide you will see a picture of a flag with a white dot in the middle. Stare at the dot until the screen changes. Do not take your eyes off of the white dot.



Trichromatic theory cannot account for afterimages like the one that you just saw (and may still be seeing). In order to explain such perceptual phenomena, a theory is needed that explains photoreceptor activity differently.

Acknowledgments

Slide # Image Description Image Source

text template upside down blue sky & grass ©iStockphoto.com/Konrad Lew

chapter template

hand touching grass ©iStockphoto.com/Catalin Plesa

3 looking ©iStockphoto.com/Leah Marshall

4 child and adult looking at same thing ©iStockphoto.com/hanhanpeggy

5 Indian woman cooking ©iStockphoto.com/Vikram Raghuvanshi Photography

5 U.S. woman cooking ©iStockphoto.com/Frantysek

6 diagram: eye Adapted from LivePsych by Pearson, Inc.

8 icon: wanted sign Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt

8 car on road ©iStockphoto.com/slobo

9 scale ©iStockphoto.com/Alex Slobodkin

9 feather ©iStockphoto.com/Tihis

10 diagram: sensory threshold Morris/Maisto, 9/e p. 83

11 pierced man ©iStockphoto.com/anna karwowska

12 bucket of popcorn ©iStockphoto.com/PMSI Web Hosting and Design

13 ESP person ©iStockphoto.com/Juanmonino

15 video: pupil Adapted from LivePsych by Pearson, Inc.

15 video: pen Adapted from LivePsych by Pearson, Inc.

15 diagram: eye Adapted from LivePsych by Pearson, Inc.

16 diagram: electromagnetic spectrum Morris/Maisto, 9/e p. 87

17 book ©iStockphoto.com/José Carlos Pires Pereira

17 wood desk ©iStockphoto.com/tanya costey

17 receptor cells animations Tutis Villis

18 table: rods & cones Morris/Maisto, 9/e p. 86

18 book ©iStockphoto.com/José Carlos Pires Pereira

18 wood desk ©iStockphoto.com/tanya costey

19 dark night ©iStockphoto.com/Soubrette

19 bright day ©iStockphoto.com/Online Creative Media

20 Open Your Book - textbook cover Shutterstock

20 Open Your Book - textbook background From Ciccarelli, Psychology, 1/e pp. 213-214

20 Open Your Book - open textbook From Ciccarelli, Psychology, 1/e pp. 114-115

20 illustration: afterimage Morris/Maisto, 9/e p. 88

21 icon: helmet ©istockphoto.com/Li Shen Jun

21 illustration: eye structure Adapted from LivePsych by Pearson, Inc.

22 illustration: brain hemispheres & vision Morris/Maisto, 9/e p. 89

23 illustration: saturation and brightness Morris/Maisto, 9/e p. 90

24 illustration:additive color Morris/Maisto, 9/e p. 91

24 illustration:subtractive color Morris/Maisto, 9/e p. 91

25 red, green, blue color wavelengths animations Derek Borman

25 vase of flowers ©iStockphoto.com/ryasick

26 icon: classic studies car ©istockphoto.com/Brian Sullivan

27 icon: wanted sign Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt

27 scrap of paper ©istockphoto.com/Trevor Hunt

27 red roses ©iStockphoto.com/borchee

29 piano ©iStockphoto.com/Christian Waadt

29 sound: high note, wavelengths Derek Borman

29 sound: low note, wavelengths Derek Borman

30 woman singing ©iStockphoto.com/afhunta

30 sound: volume, wavelengths Derek Borman

31 chart: decibels Morris/Maisto, 9/e p. 95

31 earphones ©iStockphoto.com/Aldra

32 piano and violin ©iStockphoto.com/Yenwen Lu

33 illustrations: structure of the ear Adapted from LivePsych by Pearson, Inc. and Tutis Villis

34 illustration: hair cell Morris/Maisto, 9/e p. 96

35 sound: high note Derek Borman

35 sound: low note Derek Borman

35 illustration: theories of hearing Adapted from LivePsych by Pearson, Inc. and Tutis Villis

37 person signing ©iStockphoto.com/Fotofrank

39 illustration: smell Morris/Maisto, 9/e p. 100

40 illustration: taste Morris/Maisto, 9/e p. 101

41 standing on hand ©iStockphoto.com/Get4Net

42 massage ©iStockphoto.com/Stills

43 brain ©iStockphoto.com/Henrik Jonsson

43 back pain ©iStockphoto.com/Mads Abildgaard

43 acupuncture ©iStockphoto.com/TouchPhotography

45 rubber bands ©iStockphoto.com/Shag Photo

46 architectural background ©iStockphoto.com/Jorge Delgado

46 berries ©iStockphoto.com/Amriphoto

46 flea market table ©iStockphoto.com/ROMA-OSLO

46 rubber bands ©iStockphoto.com/Shag Photo

47 yellow spider on yellow flower ©iStockphoto.com/Dmitry Galanternik

48-50 Gestalt principles animations Derek Borman

51 tangled roots ©iStockphoto.com/avi T

52 Open Your Book - textbook cover Shutterstock

52 Open Your Book - textbook background From Ciccarelli, Psychology, 1/e pp. 213-214

52 Open Your Book - open textbook From Ciccarelli, Psychology, 1/e pp. 114-115

53 icon: helmet ©istockphoto.com/Li Shen Jun

53 spyglass ©iStockphoto.com/On The Spot Images

54 night cityscape ©iStockphoto.com/adamkaz

54 spyglass ©iStockphoto.com/On The Spot Images

55 road w/ trees ©iStockphoto.com/pixonaut

55 spyglass ©iStockphoto.com/On The Spot Images56 man mountains in distance ©iStockphoto.com/Sportstock56 spyglass ©iStockphoto.com/On The Spot Images57 tree ©iStockphoto.com/Maksym Bondarchuk57 spyglass ©iStockphoto.com/On The Spot Images57 road with tree ©iStockphoto.com/AVTG58 flat rocks to water ©iStockphoto.com/Arnau Design58 spyglass ©iStockphoto.com/On The Spot Images59 sphere ©iStockphoto.com/Sean Gladwell59 spyglass ©iStockphoto.com/On The Spot Images60 kids looking out window ©iStockphoto.com/Marina Dyakonova60 lamb ©iStockphoto.com/Life on White60 spyglass ©iStockphoto.com/On The Spot Images60 goose ©iStockphoto.com/Online Creative Media60 mountains with lake ©iStockphoto.com/Studio 9Fifteen60 mountains with meadow ©iStockphoto.com/browndogstudios60 mountains ©iStockphoto.com/Edward Shnekendorf61 binoculars ©iStockphoto.com/Alex Staroseltsev62 illustration: location of sounds Morris/Maisto, 9/e p. 11364 illustraton: perceptual illusions Morris/Maisto, 9/e p. 11565 diverse people with different reactions ©iStockphoto.com/ALiJA67 topbar: wanted sign Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt67 topbar: cactus ©istockphoto.com/Lee Daniels67 topbar: wooden board ©istockphoto.com/andynwt69 carousel ©iStockphoto.com/Monique Harris71 smokestacks ©iStockphoto.com/AVTG73 topbar: helmets ©istockphoto.com/Li Shen Jun73 topbar: athletic field ©istockphoto.com/Jamie Otterstetter74 icon: classic studies car ©istockphoto.com/Brian Sullivan74 topbar: chrome & license plate ©istockphoto.com/Grafissimo74 topbar:red shiny car background ©istockphoto.com/Jon Helgason75 flag color afterimage From Ciccarelli, Psychology, 2/e p. 10078 topbar: wanted sign Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt78 topbar: cactus ©istockphoto.com/Lee Daniels78 topbar: wooden board ©istockphoto.com/andynwt78 text messaging ©iStockphoto.com/Freeze Frame Studio, Inc.79 topbar: helmets ©istockphoto.com/Li Shen Jun79 topbar: athletic field ©istockphoto.com/Jamie Otterstetter