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Psychology Chapter 3 Introduction
- 1. Understanding PsychologyELEVENTH EDITION Charles G. Morris, Albert A. Maisto Sensation and Perception Chapter 3
- 2. Links to Learning Objectives Learning Objectives LO 3.1 Describe how energy is converted into a message to the brain. Explain what is meant by the “doctrine of specific nerve energies. LO 3.2 Explain the difference between absolute and difference thresholds and the effect of adaptation on sensory thresholds. Summarize the evidence for subliminal perception. LO 3.3 Describe the parts of the eye. Explain the causes of afterimages, how dark and light adaptation affect our vision, and how light energy is converted into messages to the brain. LO 3.4 Distinguish among hue, saturation, brightness, and additive and subtractive color mixing. Explain the two major theories of color perception. LO 3.5 Explain the characteristics of sound waves and their effect on the sensation we call sound. LO 3.6 Describe the path that information about sound travels from the ears to the brain. LO 3.7 Explain place theory, frequency theory, and the volley principle. Discuss damage to the sense of hearing. LO 3.8 Describe the olfactory system and the ways stimuli give rise to smells. LO 3.9 Describe how stimuli give rise to tastes. LO 3.10 Distinguish between the kinesthetic and vestibular senses.
- 3. Links to Learning Objectives LO 3.11 Explain how sensory messages are sent from the skin to the brain. LO 3.12 Summarize the sources of differences among people in the degree of pain they experience. Explain gate-control and biopsychosocial theories of pain and the ways various pain treatments work. LO 3.13 Distinguish between sensation and perception. LO 3.14 Explain the Gestalt principles of perceptual organization. LO 3.15 Describe the several perceptual constancies. LO 3.16 Identify the major cues to distance and depth, distinguishing between monocular and binocular cues. Explain how we can localize sound LO 3.17 Explain how we perceive movement, distinguishing between real movement and apparent movement. LO 3.18 Explain how visual illusions arise. LO 3.19 Describe how observer characteristics and culture can influence perception.
- 4. Enduring Issues in Sensation and Perception
- 5. Enduring Issues To what extent do our perceptual experiences accurately reflect what is in the outside world?Diversity- Universality Stability-Change Mind-Body Nature-Nurture Person-Situation
- 6. 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- Universality Stability-Change Mind-Body Nature-Nurture Person-Situation
- 7. Enduring Issues To what extent do people around the world perceive events in the same way? Diversity- Universality Stability-Change Mind-Body Nature-Nurture Person-Situation
- 8. Enduring Issues In what ways do our experiences depend on biological processes? Diversity- Universality Stability-Change Mind-Body Nature-Nurture Person-Situation
- 10. e n s a t i o n begins when energy stimulates a receptor cell in one of the sense organs LO 3.1 Describe how energy is converted into a message to the brain. Explain what is meant by the “doctrine of specific nerve energies.
- 11. What Causes Sensory Experiences? • Receptor cells • Respond to one particular form of energy • Transduction • The process of converting physical energy, such as light or sound, into electrochemical codes
- 12. What Causes Sensory Experiences? Doctrine of Specific Nerve Energies •The one-to-one relationship between stimulation of a specific nerve and the resulting sensory experience
- 13. • 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 Sensory Thresholds . LO 3.2 Explain the difference between absolute and difference thresholds and the effect of adaptation on sensory thresholds. Summarize the evidence for subliminal perception
- 14. Determining a Sensory Threshold
- 16. Adaptation Adaptation: An adjustment of the senses to the level of stimulation they are receiving
- 18. Subliminal Perception Subliminal stimuli: Stimuli below the level of conscious awareness
- 19. Vision
- 20. The Visual System LO 3.3 Describe the parts of the eye. Explain the causes of afterimages, how dark and light adaptation affect our vision, and how light energy is converted into messages to the brain Cornea Lens Pupil Iris Retina Fovea Optic Nerve Blind Spot
- 21. The Receptor Cells • Cones located in fovea – Day vision (color) • Rods in periphery – Night vision (light and dark)
- 22. The Receptor Cells • Cones located in fovea – Day vision (color) • Rods in periphery – Night vision (light and dark)
- 25. 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. AdaptationAdaptation Light adaptation: Decreased sensitivity of rods and cones in bright light
- 26. 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.” Learning Objective 3.3 (Morris & Maisto)
- 27. 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.
- 28. The Neural Connections of the Visual System
- 29. Color Vision LO 3.4 Distinguish among hue, saturation, brightness, and 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 brightness Increasing brightness
- 30. Theories of Color Vision Additive color mixing: Mixing lights of different wavelengths to create new hues Subtractive color mixing: Mixing pigments, each of which absorbs some wavelengths of light and reflects others
- 31. Theories of Color Vision Trichromatic theory: All color perception derives from three different color receptors in the retina (usually green, blue, and red).
- 32. Opponent- process theory: Three pairs of color receptors respond to determine the color you experience. • Afterimages Theories of Color Vision
- 33. Applying Psychology A Rose by Any Other Name • Recent studies on the influence of different colors • Effect of color red on achievement •Elliot et al. •Hagemann et al.
- 34. Hearing
- 35. Sound Frequency Sound waves measured as cycles per second (hertz) Pitch Determined by frequency How high or low LO 3.5 Explain the characteristics of sound waves and their effect on the sensation we call sound.
- 36. Sound Amplitude: decibels Volume – soft to loud
- 37. A Decibel Scale for Common Sounds Prolonged exposure to sounds above 85 decibels can cause permanent ear damage. • Power lawnmower, food blender • Heavy traffic, vacuum cleaner, dishwasher • Normal conversation • Window air conditioner • Patter of rain • Average office interior • Leaves rustling • Whisper (5 feet away) 100 80 60 40 20 0
- 38. Sound Overtones: primary determinant of timbre • A note played on a piano differs from a note played on a violin because instruments have different overtones.
- 39. The Ear LO 3.6 Describe the path that information about sound travels from the ears to the brain.
- 40. Detailed Drawing of a Hair Cell
- 41. Basilar Membrane High pitch Low pitch Theories of Hearing PLACE Theory 1 FREQUENCY Theory 2 VOLLEY Theory 3 LO 3.7 Explain place theory, frequency theory, and the volley principle. Discuss damage to the sense of hearing.
- 42. pitch is determined by the location of greatest vibration on the basilar membrane. pitch is determined by the frequency with which hair cells in the cochlea fire. Receptors in the ear fire in sequence: one group, then a second, then a third, etc. – so the complete pattern of firing corresponds to sound wave frequency. Theories of Hearing PLACE Theory 1 FREQUENCY Theory 2 VOLLEY Theory 3
- 43. • Approx. 28 million Americans have some form of hearing loss – 10 million are victims of exposure to noise. – About 6.5 million teenagers have some hearing loss • Increase of nearly one-third from the levels in 1988–1994 • Treatments – Hearing aids, surgery, cochlear implant Hearing Disorders
- 44. The Other Senses
- 45. Smell LO 3.8 Describe the olfactory system and the ways stimuli give rise to smells.
- 46. Pheromones • Are chemicals that communicate information to other organisms through smell. • Pheromone receptors are located in the roof of the nasal cavity. • Can have quite specific and powerful effects on behavior. • Some animals use in daily living for • marking territory • identifying sexually receptive mates • recognizing their own species
- 47. Taste LO 3.9 Describe how stimuli give rise to tastes.
- 48. LO 3.10 Distinguish between the kinesthetic and vestibular senses. Speed and direction of movement in space Equilibrium and body position in space Kinesthetic and Vestibular Senses
- 49. The skin’s nerve receptors send nerve fibers to the brain by two routes: LO 3.11 Explain how sensory messages are sent from the skin to the brain. • medulla, thalamus sensory cortex • thalamus reticular formation The Skin Sense
- 50. Pain LO 3.12 Summarize the sources of differences among people in the degree of pain they experience. Explain gate-control and biopsychosocial theories of pain and the ways various pain treatments work. Two Theories Gate control theory Biopsychosocial theory Two Theories Gate control theory Biopsychosocial theory
- 52. Perception
- 53. The brain’s process of organizing and making sense of sensory information. e r c e p t i o n LO 3.13 Distinguish between sensation and perception.
- 54. Based on the idea that people have a natural tendency to force patterns onto whatever they see Perceptual Organization: Gestalt Principles LO 3.14 Explain the Gestalt principles of perceptual organization.
- 55. Figure Ground Perceptual Organization: Gestalt Principles Proximity Closure Continuity Similarity
- 56. Similarity Closure Continuity Perceptual Organization: Gestalt Principles
- 57. Similarity Closure Continuity Perceptual Organization: Gestalt Principles
- 58. Similarity Closure Continuity Perceptual Organization: Gestalt Principles
- 59. Figure Ground Proximity Similarity Closure Continuity Perceptual Organization: Gestalt Principles
- 60. 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.” (Morris & Maisto) LO 3.15 Describe the several perceptual constancies
- 61. Perception of Distance and Depth LO 3.16 Identify the major cues to distance and depth, distinguishing between monocular and binocular cues. Explain how we can localize sound Monocular cues: Visual cues requiring the use of one eye • Interposition • Linear perspective • Aerial perspective • Elevation • Texture gradient • Shadowing • Motion parallax
- 62. Linear Perspective Elevation Interposition Aerial Perspective Texture Gradient Motion Parallax Shadowing
- 63. Linear Perspective Elevation Interposition Aerial Perspective Texture Gradient Motion Parallax Shadowing
- 64. Linear Perspective Elevation Interposition Aerial Perspective Texture Gradient Motion Parallax Shadowing
- 65. Linear Perspective Elevation Interposition Aerial Perspective Texture Gradient Motion Parallax Shadowing
- 66. Linear Perspective Elevation Interposition Aerial Perspective Texture Gradient Motion Parallax Shadowing
- 67. Linear Perspective Elevation Interposition Aerial Perspective Texture Gradient Motion Parallax Shadowing
- 68. Linear Perspective Elevation Interposition Aerial Perspective Texture Gradient Motion Parallax Shadowing
- 69. Perception of Distance and Depth Binocular cues: Visual cues requiring the use of both eyes • Stereoscopic vision • Retinal disparity • Convergence
- 70. Location of Sounds Monaural cues: Cues to sound location that require just one ear Binaural cues: Cues to sound location that involve both ears working together .
- 71. 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 LO 3.17 Explain how we perceive movement, distinguishing between real movement and apparent movement.
- 72. Visual Illusions Perceptual illusions: Stimulus contains misleading cues that give rise to inaccurate or impossible perceptions LO 3.18 Explain how visual illusions arise.
- 73. Motivation and emotion Values Expectations Cognitive style Experience and culture Personality LO 3.19 Describe how observer characteristics and culture can influence perception. Observer Characteristics 1 2 3 4 5 6
- 75. 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.
- 76. Image #1 (Click anywhere to begin)
- 78. Image #2 (Click anywhere to begin)
- 80. 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.
- 81. 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.
- 82. 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.
- 84. 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.
- 85. Which of your senses do you consider to be the most emotionally significant? Why?
- 86. Leave the classroom and find real-world examples for at least three of the monocular depth cues listed below. DRAW your examples and be prepared to share. Be back in 5 minutes. – Interposition – Linear perspective – Aerial perspective – Elevation – Texture gradient – Shadowing – Motion parallax
Editor's Notes
- Image credit: brain with wording, Morris/Maistro, 11/e, cover art
- Image credit: sensory receptors-Morris/Maistro, 11/e, page 83
- Image credit: looking-©iStockphoto.com/Leah Marshall
- Image credit: child and adult looking at same thing ©iStockphoto.com/hanhanpeggy
- Image credits: Indian woman cooking-©iStockphoto.com/Vikram Raghuvanshi Photography; U.S. woman cooking-©iStockphoto.com/Frantysek
- Image credit: diagram: eye -Adapted from LivePsych by Pearson, Inc.
- Image credit: sensory receptors-Morris/Maistro, 11/e, page 83
- Sensation – occurs when energy from an external or internal source stimulates a receptor cell in one or more sense organs. receptor cell - a specialized cell that responds to a particular type of energy. transduction - the conversion of physical energy into coded neural signals. Image credit: icon: wanted sign - Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt, car on road-©iStockphoto.com/slobo
- Image credit:five senses - ©istockphoto.com/1 design
- Image credit: colored smoke - ©istockphoto.com/Wolfgang Amri
- Absolute thresholds – the smallest amount of energy needed for conscious detection of a stimulus at least half the time it is present. Difference threshold or just-noticeable difference – the smallest change in stimulation that can be detected 50% of the time. Producing a jnd for sound requires a 0.3% change. Producing a jnd for taste requires a 20% change. Producing a jnd for weight requires a 2% change. Weber’s law – the principle that the jnd for any given sense is a constant fraction or proportion of the stimulation being judged. Image credit: scale-©iStockphoto.com/Alex Slobodkin, Feather-©iStockphoto.com/Tihis
- The red line represents an ideal case: At all intensities below the threshold, the person reports no sensation or no change in intensity; at all intensities above the threshold, the person reports a sensation or a change in intensity. In reality, however, we never come close to the ideal of the red line. The blue line shows the actual responses of a typical person. The threshold is taken as the point where a person reports a sensation or a change in intensity 50% of the time. Image credit: diagram: sensory threshold Morris/Maisto, 11/e p. 85
- Image credit: pierced man-©iStockphoto.com/anna karwowska
- Some messages occur subliminally – below one’s level of awareness. The ongoing debate is whether or not subliminal messages influence behavior. In a controlled laboratory setting, people can process and respond to information presented subliminally. Subliminal message outside the laboratory have no significant effect on behavior. Image credit: bucket of popcorn-©iStockphoto.com/PMSI Web Hosting and Design
- Image credit:sensory receptors-Morris/Maistro, 11/e, page 83
- The Structures of the Eye: Cornea – transparent protective covering over the front part of the eye. Pupil – a small opening in the iris through which light enters the eye. Iris – the colored part of the eye that regulates the size of the pupil. Lens – the transparent part of the eye behind the pupil that focuses light onto the retina Retina – the lining of the eye containing receptor cells that are sensitive to light. Fovea – the area of the retina that is the center of the visual field. Optic nerve – the bundle of axons of ganglion cells that carries neural messages from each eye to the brain (see slide 21). Blind spot – the place on the retina where the axons of all the ganglion cells leave the eye and where there are no receptors (see slide 21). Image credit: video: pen-Adapted from LivePsych by Pearson, Inc. , diagram: eye-Adapted from LivePsych by Pearson, Inc.
- Rods – receptor cells in the retina responsible for night vision and perception of brightness. Cones – receptor cells in the fovea responsible for color vision. Bipolar cells – neurons that have only one axon and one dendrite; in the eye, these neurons connect the receptors on the retina to the ganglion cells. Visual acuity – the ability to distinguish fine details visually. Image credit:book-©iStockphoto.com/José Carlos Pires Pereira, wood desk-©iStockphoto.com/tanya costey, receptor cells animations-Tutis Villis
- Rods – receptor cells in the retina responsible for night vision and perception of brightness. Cones – receptor cells in the fovea responsible for color vision. Bipolar cells – neurons that have only one axon and one dendrite; in the eye, these neurons connect the receptors on the retina to the ganglion cells. Visual acuity – the ability to distinguish fine details visually. Image credit:book-©iStockphoto.com/José Carlos Pires Pereira, wood desk-©iStockphoto.com/tanya costey, receptor cells animations-Tutis Villis
- Image credits: table: rods & cones-Morris/Maisto, 11/e p. 89, book-©iStockphoto.com/José Carlos Pires Pereira, wood desk-©iStockphoto.com/tanya costey
- The retina contains receptor cells that are responsible for vision. The eye is sensitive to only to a very small segment of the spectrum of electromagnetic energy known as visible light. Energies in the electromagnetic spectrum are referred to by their wavelength. Wavelengths – the different energies represented in the electromagnetic spectrum. Image credit diagram: electromagnetic spectrum-Morris/Maisto, 11/e p. 89
- Adaptation – the process by which our senses adjust to different levels of stimulation. Dark adaptation – increased sensitivity of rods and cones in darkness. First the cones and then the rods slowly adapt (over the course of 30 minutes) until they reach their maximum sensitivity. Light adaptation – decreased sensitivity of rods and cones in bright light. When moving from darkness to bright light, the rods and cones become less sensitive to light (over the course of 1 minute). Image credits: dark night-©iStockphoto.com/Soubrette, bright day-©iStockphoto.com/Online Creative Media
- Afterimage – sense experience that occurs after a visual stimulus has been removed. Image credit: Open Your Book - textbook background-From Ciccarelli, Psychology, 1/e pp. 213-214, Open Your Book - open textbook-From Ciccarelli, Psychology, 1/e pp. 114-115, illustration: afterimage-Morris/Maisto, 11/e p 91
- Bipolar cells – neurons that have only one axon and one dendrite; in the eye, these neurons connect the receptors on the retina to the ganglion cells. Ganglion cells – neurons that connect the bipolar cells in the eyes to the brain. Optic nerve – the bundle of axons of ganglion cells that carries neural messages from each eye to the brain. Blind spot – the place on the retina where the axons of all the ganglion cells leave the eye and where there are no receptors. Image credit: illustration: eye structure-Adapted from LivePsych by Pearson, Inc.
- Messages about the red-colored area in the left vision field of each eye travel to the right occipital lobe; information about the blue area in the right visual field of each eye goes to the left occipital lobe. The crossover point is the optic chiasm. Optic chiasm – the point near the base of the brain where some fibers in the optic nerve from each eye cross to the other side of the brain. Feature detectors – specialized brain cells that only respond to particular elements in the visual field such as movement or lines of specific orientation. Image credit: illustration: brain hemispheres & vision-Morris/Maisto, 11/e p. 92, Adapted from “The Split Brain of Man,” by Michael S. Gazzaniga, illustrations by Eric O. Mose. Copyright ©1967. Reprinted by permission of the estate of Eric Mose
- Image credit:illustration: saturation and brightness-Morris/Maisto, 9/e p. 90
- Image credits: illustration:additive color-Morris/Maisto, 9/e p. 91, illustration:subtractive color-Morris/Maisto, 9/e p. 91
- This theory of color vision was proposed by Hermann von Helmholtz. Image credit: red, green, blue color wavelengths animations-Derek Borman, vase of flowers-©iStockphoto.com/ryasick
- This theory of color vision was proposed by Ewald Hering. Image credit:icon: classic studies car ©istockphoto.com/Brian Sullivan
- Image credits:icon: wanted sign-Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt, scrap of paper-©istockphoto.com/Trevor Hunt, red roses-©iStockphoto.com/borchee, Piano-©iStockphoto.com/Christian Waadt
- Image credit:sensory receptors-Morris/Maistro, 11/e, page 83
- Sound – a psychological experience created by the brain in response to changes in air pressure that are received by the auditory system. Sound Waves – changes in pressure caused when molecules of air or fluid collide with one another and then move apart again. Frequency – the number of cycles per second in a wave. Hertz (Hz) – unit of measurement (in cycles per second) for the frequency of sound waves. The human ear responds to frequencies from approximately 20 to 20,000 Hz. In sound, frequency is the primary determinant of pitch. Pitch – auditory experience corresponding primarily to frequency of sound vibrations resulting in a higher or lower tone. Image credits: sound: high note, wavelengths-Derek Borman, sound: low note, wavelengths-Derek Borman
- Amplitude – the magnitude of a wave; in sound, the primary determinant of loudness. Decibel – unit of measurement for the loudness of sounds. As we grow older, we lose some of our ability to hear soft sounds. Image credits: woman singing-©iStockphoto.com/afhunta, sound: volume, wavelengths-Derek Borman
- Image credits: chart: decibels-Morris/Maisto, 11/e p. 97, earphones-©iStockphoto.com/Aldra
- Overtones – tones that result from sound waves that are multiples of the basic tone; primary determinant of timbre. Timbre – the quality or texture of a sound; caused by overtones. Image credit: piano and violin-©iStockphoto.com/Yenwen Lu
- Sound waves gathered by the outer ear are passed along to the eardrum, causing it to vibrate. The vibration of the eardrum causes the hammer, the anvil, and stirrup to hit each other in sequence, amplifying and carrying the vibrations to the oval window and on to the fluid in the cochlea of the inner ear. In the inner ear, movement of the basilar membrane stimulates sensory receptors in the organ of Corti, and this stimulation of the hair cells (see next slide) produces auditory signals that travel to the brain through the auditory nerve. Oval window – membrane across the opening between the middle ear and inner ear that conducts vibrations to the cochlea. Cochlea – part of the inner ear containing fluid that vibrates, which in turn causes the basilar membrane to vibrate. Basilar membrane – vibrating membrane in the cochlea of the inner ear; it contains sense receptors for sound. Organ of Corti – structure on the surface of the basilar membrane that contains the receptor cells for hearing. Auditory nerve – the bundle of axons that carries signals from each ear to the brain. Neural Connections: Each ear sends messages to both cerebral hemispheres. The nerve fibers from the ears cross over in the medulla, and then they are sent to various areas of the brain. Ultimately, their destination is the temporal lobe of each hemisphere. Image credit: illustrations: structure of the ear-Adapted from LivePsych by Pearson, Inc. and Tutis Villis
- Organ of Corti – structure on the surface of the basilar membrane that contains the receptor cells for hearing. At the top of each hair cell is a bundle of fibers. If the fibers bend as much as 100 trillionths of a meter, the receptor cells transmit a sensory message to the brain. Image credit: illustration: hair cell-Morris/Maisto, 11/e p. 100
- Loudness is determined primarily by how many neurons are activated. The coding of pitch is more complicated. There are two views of pitch discrimination: Place theory – pitch is determined by the location of greatest vibration in the basilar membrane. Frequency theory – pitch is determined by the frequency with which hair cells in the cochlea fire. Volley principle – refinement of frequency theory; it suggests that receptors in the ear fire in sequence, with one group responding, then a second, then a third, and so on, so that the complete pattern of firing corresponds to the frequency of the sound wave. Image credit: sound: high note=Derek Borman, sound: low note-Derek Borman, illustration: theories of hearing-Adapted from LivePsych by Pearson, Inc. and Tutis Villis
- Image credit:
- Deafness: Approximately 28 million Americans have some form of hearing loss, and about 10 million of those cases are the result of exposure to noise (e.g., leaf blowers, chain saws, etc.). Hearing aids that utilize digital technology can enhance speech sounds while reducing background noise. Surgery can help those with conductive hearing loss due to a stiffening of the connections between the bones of the middle ear. If deafness results from cochlear damage, implants can be surgically inserted that transmit electrical signals through a synthesizer directly to the auditory nerve, which then conveys an auditory message to the brain. If a child is born deaf or become deaf at an early age, the National Association of the Deaf argues that surgical procedures that only partially restore hearing may not prove beneficial to the child. Tinnitus: Tinnitus is a hearing disorder affecting 1 in 8 people. Its symptom is a steady, high-pitched hum that does not go away. In some cases, the sound can be unbearably loud. Tinnitus results from irritation or damage to the hair cells that can be caused by loud sounds or toxins, certain medical conditions, and some antibiotics. Drug therapies, implants that create “white noise,” and biofeedback are used to treat tinnitus. Image credit: person signing-©iStockphoto.com/Fotofrank
- Image credit:sensory receptors-Morris/Maistro, 11/e, page 83
- How humans smell remains an open question. When we inhale, the air we breathe flows over approximately 12 million odor-detecting cells in the naval cavity. Each of these cells responds only to some odorant molecules, sending messages to the olfactory bulb, and then on to the olfactory cortex in the temporal lobes of the brain where we are able to recognize and remember about 10,000 different smells. How the message from the nose results in the sensation of smell remains a mystery. Odor sensitivity is related to gender and age. Women and adults age 20-40 have the best sense of smell. Olfactory bulb – the smell center in the brain. Pheromones – chemicals that communicate information to other organisms through smell. Image credit: illustration: smell-Morris/Maisto, 9/e p. 100; Source: Human Anatomy and Physiology by Anthony J. Gaudin and Kenneth C. Jones. Copyright © 1989. Reprinted by permission
- Taste (the sensory qualities of sweet, sour, salty, bitter, and umami – sensitivity to MSG and other proteins) is different from flavor (a complex interaction of taste and smell). Taste buds – structures on the tongue that contain the receptor cells for taste. All areas of the tongue can distinguish all taste qualities, but some areas may be more sensitive to certain tastes than others. The sensation of taste occurs when the chemical substances in the food we eat come into contact with the taste buds. The taste buds then release a neurotransmitter that causes adjacent neurons to fire, sending a nerve impulse to the parietal lobe of the brain and to the limbic system. Image credit: illustration: taste=Morris/Maisto, 11/e p. 104
- Kinesthetic senses – senses of muscular movement, posture and strain on muscles and joints. Receptors provide constant feedback from the stretching and contraction of muscles. This information travels via the spinal cord to the parietal lobes (the same brain area that perceives the sense of touch). Vestibular senses – the senses of equilibrium and body position in space. The vestibular senses originate in the inner ear, where the impulses from hair cells travel to the brain along the auditory nerve. Some messages from the vestibular senses go to the cerebellum (which plays a role in reflexes and coordinated movement) while other go to the parietal lobe for analysis and response. Image credit: standing on hand=©iStockphoto.com/Get4Net
- The Skin Senses The skin is the largest sense organ. Some information from the receptors in the skin is sent through the medulla and thalamus to the sensory cortex of the parietal lobes of the brain. Other information goes through the thalamus and then to the reticular formation, which is responsible for arousal of the nervous system. Skin receptors contribute to sensations of pressure, temperature, and pain. The skin senses are remarkably sensitive, especially those in the face and fingertips. Image credit:massage-©iStockphoto.com/Stills
- More people visit doctors for relief of pain than for any other reason. Yet, the sensation of pain in many ways remains mysterious. Gate-Control Theory – the theory that a “neurological gate” in the spinal cord controls the transmission of pain messages to the brain; if the gate is open, we experience more pain than when the gate is closed. Biopsychosocial Theory – the theory that the interaction of biological, psychological and cultural factors influences the intensity and duration of pain. Biological mechanisms involve the degree to which tissue is injured and our pain pathways have adapted. Genetics also plays a role in pain sensitivity. Psychological mechanisms such as thoughts, beliefs and emotions can affect our experience of pain. For example, the amount of pain people expect to feel is predictive of how much pain they actually perceive. The ability to cope with pain also mediates the perception of pain. Social mechanisms such as the degree of family support can also influence pain perception. Those who report greater levels of family support report lower levels of perceived pain, less reliance on medication, and greater activity levels than those with lower levels of family support. Alternative Treatments There are many treatments available for reducing pain, though none of them is fully effective against all kinds of pain. This has given rise to many “alternative medicine” approaches for controlling chronic pain. How they work to reduce pain is often not clear. Placebo effect – pain relief that occurs when a person believes a pill or procedure will reduce pain. The actual cause of the relief seems to come from endorphins. Image credit:brain-©iStockphoto.com/Henrik Jonsson, back pain-©iStockphoto.com/Mads Abildgaard, Acupuncture-©iStockphoto.com/TouchPhotography
- Image credit:sensory receptors-Morris/Maistro, 11/e, page 83
- Image credit: rubber bands-©iStockphoto.com/Shag Photo
- Gestalt psychologists believed that the brain creates a coherent perceptual experience that is more than simply the sum of the available sensory information and that is does so in predictable ways. Image credits: architectural background-©iStockphoto.com/Jorge Delgado, Berries-©iStockphoto.com/Amriphoto, flea market table-©iStockphoto.com/ROMA-OSLO, rubber bands-©iStockphoto.com/Shag Photo
- One of the basic perceptual processes involves distinguishing the object of one’s attention (i.e.., the “figure”) from the background (i.e., “ground”).Image credit: yellow spider on yellow flower-©iStockphoto.com/Dmitry Galanternik
- Proximity – when objects are close to one another, we tend to perceive them together rather than separately. Image credits: Gestalt principles animations-Derek Borman
- Similarity – objects that are of a similar color, size, or shape are usually perceived as part of a pattern. Image credits: Gestalt principles animations-Derek Borman
- Closure – we are inclined to overlook incompleteness in sensory information and to perceive a whole object even when none really exists. Image credits: Gestalt principles animations-Derek Borman
- Continuity – items that continue a pattern or direction tend to be grouped together as part of the pattern. Image credit: tangled roots-©iStockphoto.com/avi T
- Perceptual constancy – a tendency to perceive objects as stable and unchanging despite changes in sensory stimulation. Size constancy – the perception of an object as the same size regardless of the distance from which it is viewed. Shape constancy – a tendency to see an object as the same shape no matter what angle it is viewed from. Color constancy – an inclination to perceive familiar objects as retaining their color despite changes in sensory information. Brightness constancy – the perception of brightness as the same, even though the amount of light reaching the retina changes. Image credit: Open Your Book - textbook background-From Ciccarelli, Psychology, 1/e pp. 213-214,Open Your Book - open textbook-From Ciccarelli, Psychology, 1/e pp. 114-115
- We use many cues to determine the distance and depth of objects, some of which can be processed using one eye (monocular cues) while other cues require two eyes (binocular cues). Image credit: icon: helmet-©istockphoto.com/Li Shen Jun, Spyglass-©iStockphoto.com/On The Spot Images
- Interposition – monocular distance cue in which one object, by partly blocking a second object is perceived as being closer. Image credit: night cityscape-©iStockphoto.com/adamkaz, Spyglass-©iStockphoto.com/On The Spot Images
- Linear perspective – monocular cues to distance and depth based on the fact that two parallel lines seem to come together at the horizon. Image credit: road w/ trees-©iStockphoto.com/pixonaut, spyglass-©iStockphoto.com/On The Spot Images
- Aerial perspective – monocular cue to distance and depth based on the fact that more distant objects are likely to appear hazy and blurred. Image credits: man mountains in distance-©iStockphoto.com/Sportstock, Spyglass-©iStockphoto.com/On The Spot Images
- Elevation – monocular cue to distance and depth based on the fact that the higher on the horizontal plane an object is, the farther away it appears. Image credits: tree-©iStockphoto.com/Maksym Bondarchuk, Spyglass-©iStockphoto.com/On The Spot Images, road with tree-©iStockphoto.com/AVTG
- Texture gradient – monocular cue to distance and depth based on the fact that objects seen at greater distances appear to be smoother and less textured. Image credit: flat rocks to water-©iStockphoto.com/Arnau Design, Spyglass-©iStockphoto.com/On The Spot Images
- Shadowing – monocular cue to distance and depth based on the fact that shadows often appear on the parts of objects that are more distant. Image credits: sphere-©iStockphoto.com/Sean Gladwell, Spyglass-©iStockphoto.com/On The Spot Images
- Motion parallax – monocular distance cue in which objects closer than the point of visual focus seem to move in the direction opposite to the viewer’s moving head, and objects beyond the focus point appear to move in the same direction as the viewer’s head. Image credits: kids looking out window-©iStockphoto.com/Marina Dyakonova, Lamb-©iStockphoto.com/Life on White, spyglass-©iStockphoto.com/On The Spot Images, Goose-©iStockphoto.com/Online Creative Media, mountains with lake-©iStockphoto.com/Studio 9Fifteen, mountains with meadow-©iStockphoto.com/browndogstudios,Mountains-©iStockphoto.com/Edward Shnekendorf
- Binocular cues – visual cues requiring the use of both eyes. Stereoscopic vision – combination of two retinal images to give a three-dimensional perceptual experience. Retinal disparity – binocular distance cue based on the difference between the images cast on the two retinas when both eyes are focused on the same object. Convergence – a visual depth cue that comes from muscles controlling eye movement as the eyes turn inward to view a nearby stimulus. Image credit: binoculars-©iStockphoto.com/Alex Staroseltsev
- Sounds waves coming from source B will reach both ears simultaneously. A sound wave from source A reaches the ear first, where it is also louder. The head casts a “shadow” over the other ear, thus reducing the intensity of the delayed sound in that ear. We locate the source of sounds by using both monaural (single-ear) and binaural (two-ear) cues. One monaural cue involves loudness; loud sounds are perceived as closer than faint sounds, and changes in loudness are perceived as changes in distance. One binaural cue also involves loudness. Sound signals arriving from a source off to one side of a person will be louder in the ear nearer to the source than the ear farther from the source (because the head partially blocks the sound). Another binaural cue involves the timing of sounds; sound signals will reach the ear closer to the source of the sound before they reach the other ear, indicating which direction from the person the source of the sound is located. Image credit: illustration: location of sounds- Morris/Maisto, 9/e p. 113, Source: From Foundations of Psychology by E.G. Boring, H.S. Langfeld, & H.P. Weld (1976). Reprinted by permission of John Wiley & Sons
- Perception of movement is a complicated process involving: Visual messages from the retina Messages from the muscles around the eyes as they shift to follow a moving object Autokinetic illusion – the perception that a stationary object is actually moving. Stroboscopic motion – apparent movement that results from flashing a series of still pictures in rapid succession, as in a motion picture. Phi phenomenon – apparent movement caused by flashing lights in a sequence as on a theater marquee.
- When we experience a visual illusion, we are fooled into “seeing” something that is not there. Perceptual illusions occur because the stimulus contains misleading cues that give rise to inaccurate or impossible perceptions. Image credit: illustraton: perceptual illusions=Morris/Maisto, 9/e p. 115
- Despite the fact that all humans have the same sense organs and perceptual capabilities, several personal factors can influence one’s perceptions. Motivation and Emotion – People’s desires, needs and fears shape their perceptions. Values – The value that people place on an object can influence their perception of the object. Expectations – People see what they expect to see, overlooking stimuli that are inconsistent with their expectations. Cognitive style – People develop ways of dealing with the environment that affect how they perceive the world. For example, field-dependent individuals tend to perceive the environment as a whole and do not tend to focus on individual features or objects in their visual field. Field-independent individuals tend to maintain perceptual distinctions among the various aspects of their visual environment. Experience and Culture – Cultural differences cause people to attend to different things while viewing the same image; a person’s attention is often drawn to what is novel. Also, a person with much experience or expertise in a subject can perceive more subtle features of a stimulus than someone with less experience or expertise. Personality – Personality characteristics can serve to prime individuals or make them more likely to perceive stimuli that are consistent with characteristics of their personality. Image credit: diverse people with different reactions-©iStockphoto.com/ALiJA
- Image credit: sensory receptors-Morris/Maistro, 11/e, page 83
- Image credit: topbar: wanted sign-Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt, topbar: cactus-©istockphoto.com/Lee Daniels, topbar: wooden board-©istockphoto.com/andynwt
- Instructor: Behind the little girl’s right shoulder, a black carousel horse appears and disappears. Image credit: carousel-©iStockphoto.com/Monique Harris
- Instructor: The change in this slide appears on the left side. A smokestack appears and disappears. Image credit: smokestacks-©iStockphoto.com/AVTG
- This demonstration can be used to remind the students that in between sensation and perception are a whole host cognitive steps that must be completed in order for us to make sense of our world.
- Blind spot - area in the retina where the axons of the three layers of retinal cells exit the eye to form the optic nerve, insensitive to light. Image credit: topbar: helmets-©istockphoto.com/Li Shen Jun, topbar: athletic field=©istockphoto.com/Jamie Otterstetter
- Image credits:icon: classic studies car ©istockphoto.com/Brian Sullivan topbar: chrome & license plate-©istockphoto.com/Grafissimo, topbar:red shiny car background-©istockphoto.com/Jon Helgason
- Image credit: flag color afterimage-From Ciccarelli, Psychology, 2/e p. 100
- topbar: wanted sign Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt topbar: cactus ©istockphoto.com/Lee Daniels topbar: wooden board ©istockphoto.com/andynwt
- Image credits:topbar: helmets ©istockphoto.com/Li Shen Jun; topbar: athletic field©istockphoto.com/Jamie Otterstetter