Unit 3: Sensation and Perception
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Central Penn College PSY100 FL13 Z1 Unit 3 for week 3 Sensation and Perception Credit is given to authors of PSY100 textbook, Morris & Maisto (2013) as well as additional resources to include Durand & Barlow (2013). Much thanks to the publishers for shared images and slide design. PLEASE NOTE: Please refer to weekly professor guide for list of videos required in addition to this PPT presentation.
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Unit 3: Sensation and Perception
- 2. Quote of the week: One’s perception is one’s reality.
- 3. Enduring Issues Person-Situation Nature-Nurture Stability-Change DiversityUniversality To what extent do our perceptual experiences accurately reflect what is in the outside world? Mind-Body Copyright © Pearson Education 2013
- 4. Enduring Issues Person-Situation Nature-Nurture In what ways do our experiences of the outside world change as a result of experience over the course of our lives? Stability-Change DiversityUniversality Mind-Body Copyright © Pearson Education 2013
- 5. Enduring Issues Person-Situation Nature-Nurture Stability-Change To what extent do people around the world perceive events in the same way? DiversityUniversality Mind-Body Copyright © Pearson Education 2013
- 6. Enduring Issues Person-Situation Nature-Nurture In what ways do our experiences depend on biological processes? Stability-Change DiversityUniversality Mind-Body Copyright © Pearson Education 2013
- 8. ensation The experience of sensory stimulation Copyright © Pearson Education 2013
- 9. Sensory Thresholds LEARNING OBJECTIVE: Explain the difference between absolute and difference thresholds and the effect of adaptation on sensory thresholds. Summarize the evidence for subliminal perception and extrasensory perception. • 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 Copyright © Pearson Education 2013
- 10. Adaptation Adaptation: An adjustment of the senses to the level of stimulation they are receiving Copyright © Pearson Education 2013
- 11. Subliminal Perception Subliminal stimuli: Stimuli below the level of conscious awareness Copyright © Pearson Education 2013
- 12. Vision
- 13. The Visual System 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. Light enters the eye through the cornea. It passes through the pupil, and is focused by the lens onto the retina. Images adapted from LivePsych by Pearson, Inc. Copyright © Pearson Education 2013
- 14. The Receptor Cells • Cones located in fovea – Day vision (color) • Rods in periphery – Night vision (light and dark) Copyright © Pearson Education 2013
- 15. The Receptor Cells Copyright © Pearson Education 2013
- 16. Adaptation LEARNING OBJECTIVE: Explain how dark and light adaptation affect our vision and how they cause afterimages. Our eyes adjust to different levels of stimulation based on changes in the sensitivity of rods and cones. Dark adaptation: Increased sensitivity of rods and cones in darkness Light adaptation: Decreased sensitivity of rods and cones in bright light Copyright © Pearson Education 2013
- 17. 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)
- 18. 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. Images adapted from LivePsych by Pearson, Inc. Copyright © Pearson Education 2013
- 19. Beau: Optical Illusions Copyright © Pearson Education 2013
- 20. Color Vision LEARNING OBJECTIVE: Distinguish between hue, saturation, brightness, additive and subtractive color mixing. Explain the two major theories of color perception. Saturation: The vividness or richness of a hue Increasing Increasing saturation saturation Increasing Increasing brightness brightness Hues: Aspects of color that correspond to names such as red, green, and blue Brightness: The nearness of a color to white as opposed to black Copyright © Pearson Education 2013
- 21. Neil Harbisson: Hearing Color Copyright © Pearson Education 2013
- 22. Hearing
- 23. Sound LEARNING OBJECTIVE: Explain the characteristics of sound waves and their effect on the sensation we call sound. Frequency – hertz (Hz): waves (cycles) per second • Pitch – High – Low Copyright © Pearson Education 2013
- 24. Sound Amplitude: decibels Volume – soft to loud Copyright © Pearson Education 2013
- 25. The Ear 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. Images adapted from LivePsych by Pearson, Inc. Copyright © Pearson Education 2013
- 26. Hearing Disorders LEARNING OBJECTIVE: Explain the two major kinds of hearing disorders (deafness and tinnitus). 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 Copyright © Pearson Education 2013
- 27. The Other Senses
- 28. Smell LEARNING OBJECTIVE: Describe how stimuli give rise to smells and tastes. Source: Human Anatomy and Physiology by Anthony J. Gaudin and Kenneth C. Jones. Copyright © 1989. Reprinted by permission. Copyright © Pearson Education 2013
- 29. Taste Copyright © Pearson Education 2013
- 30. Kinesthetic and Vestibular Senses LEARNING OBJECTIVE: Distinguish between the kinesthetic and vestibular senses. Muscle movement Posture Strain on muscles, joints Equilibrium and body position in space Copyright © Pearson Education 2013
- 31. The Skin Sense 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. The skin’s nerve receptors send nerve fibers to the brain by two routes: • medulla, thalamus • thalamus sensory cortex reticular formation Copyright © Pearson Education 2013
- 33. Perception
- 34. erception The brain’s interpretation of sensory information so as to give it meaning Copyright © Pearson Education 2013
- 35. LEARNING OBJECTIVE: Distinguish between sensation and perception. Explain the Gestalt principles of perceptual organization. Describe the several perceptual constancies. Based on the idea that people have a natural tendency to force patterns onto whatever they see Copyright © Pearson Education 2013
- 36. Perceptual Organization: Gestalt Principles Figure Ground Proximity Closure Similarity Continuity Copyright © Pearson Education 2013
- 37. Perceptual Organization: Gestalt Principles Figure Ground Proximity Closure Similarity Continuity
- 38. Perceptual Organization: Gestalt Principles Figure Ground Proximity Closure Similarity Continuity
- 39. Perceptual Organization: Gestalt Principles Figure Ground Proximity Closure Similarity Continuity
- 40. Perceptual Organization: Gestalt Principles Figure Ground Proximity Closure Similarity Continuity
- 41. 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)
- 42. 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? Copyright © Pearson Education 2013
- 43. 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 Copyright © Pearson Education 2013
- 44. Visual Illusions LEARNING OBJECTIVE: Explain how visual illusions arise. Perceptual illusions: Stimulus contains misleading cues that give rise to inaccurate or impossible perceptions Copyright © Pearson Education 2013
- 45. Observer Characteristics LEARNING OBJECTIVE: Describe how observer characteristics and culture can influence perception. 1 Motivation and emotion 2 Values 3 Expectations 4 Cognitive style 5 Experience and culture 6 Personality Copyright © Pearson Education 2013
- 46. Other Impacts on Your Perception: Attention Copyright © Pearson Education 2013
- 47. Other Impacts on Your Perception: Perspective Copyright © Pearson Education 2013
- 48. “Smell and vision are just two of the senses giving us a window on the Quote of the week: world… [all] combine in a rich mosaic of awareness forming the One’s perception is one’s reality. basis of consciousness. It is sensation that gives us connections both to our own selves and to our surroundings” (Morris & Maisto, 2013, p. 81). Copyright © Pearson Education 2013
- 50. 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.
- 51. Image #1 (Click anywhere to begin)
- 53. Image #2 (Click anywhere to begin)
- 55. 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-bymoment basis. These are the parts that are remembered. This demonstration reminds us that the road between sensation and perception has many twists and turns.
- 56. 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.
- 57. 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.
- 58. Copyright © Pearson Education 2013
- 59. 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.
- 60. Acknowledgments
- 61. Slide # Image Description text template upside down blue sky & grass chapter template Image Source ©iStockphoto.com/Konrad Lew 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
- 62. 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 27 scrap of paper Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt ©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
- 63. 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
- 64. 55 56 56 57 57 57 58 58 59 59 60 60 60 60 60 60 60 61 62 64 65 67 67 67 69 71 73 73 74 74 74 75 78 78 78 78 79 79 spyglass man mountains in distance spyglass tree spyglass road with tree flat rocks to water spyglass sphere spyglass kids looking out window lamb spyglass goose mountains with lake mountains with meadow mountains binoculars illustration: location of sounds illustraton: perceptual illusions diverse people with different reactions topbar: wanted sign topbar: cactus topbar: wooden board carousel smokestacks topbar: helmets topbar: athletic field icon: classic studies car topbar: chrome & license plate topbar:red shiny car background flag color afterimage topbar: wanted sign topbar: cactus topbar: wooden board text messaging topbar: helmets topbar: athletic field ©iStockphoto.com/On The Spot Images ©iStockphoto.com/Sportstock ©iStockphoto.com/On The Spot Images ©iStockphoto.com/Maksym Bondarchuk ©iStockphoto.com/On The Spot Images ©iStockphoto.com/AVTG ©iStockphoto.com/Arnau Design ©iStockphoto.com/On The Spot Images ©iStockphoto.com/Sean Gladwell ©iStockphoto.com/On The Spot Images ©iStockphoto.com/Marina Dyakonova ©iStockphoto.com/Life on White ©iStockphoto.com/On The Spot Images ©iStockphoto.com/Online Creative Media ©iStockphoto.com/Studio 9Fifteen ©iStockphoto.com/browndogstudios ©iStockphoto.com/Edward Shnekendorf ©iStockphoto.com/Alex Staroseltsev Morris/Maisto, 9/e p. 113 Morris/Maisto, 9/e p. 115 ©iStockphoto.com/ALiJA Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt ©istockphoto.com/Lee Daniels ©istockphoto.com/andynwt ©iStockphoto.com/Monique Harris ©iStockphoto.com/AVTG ©istockphoto.com/Li Shen Jun ©istockphoto.com/Jamie Otterstetter ©istockphoto.com/Brian Sullivan ©istockphoto.com/Grafissimo ©istockphoto.com/Jon Helgason From Ciccarelli, Psychology, 2/e p. 100 Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt ©istockphoto.com/Lee Daniels ©istockphoto.com/andynwt ©iStockphoto.com/Freeze Frame Studio, Inc. ©istockphoto.com/Li Shen Jun ©istockphoto.com/Jamie Otterstetter
Notas do Editor
- How do you know what you see is there?
- Does it reflect me, you or the situation?
- As I develop and begin to expect of the outside world, do those expectations come true? We will learn that while the sensory information may be the same, our perception varies based on us.
- At the end we will highlight how individuals have different experiences based on a variety of personal factors which you will later discuss in the discussion board. But remember neural plasticity? If the neural pathways are similar, are then expectations similar so perception is similar?
- There is much on the biological processes of the senses in this chapter. In what ways do our experiences depend on the biological processes?
- Let’s establish what sensation is first.
- 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. This is what happens. There is energy in the environment. An example of energy is a sound wave, a vibration of air molecules. When that energy stimulates a receptor cell, which a specialized cell that is designed for that particular type of energy, a series of dominos is started. It does not mean the ear interprets the information. Sensation is simply the experience of sensory stimulation. If you consider what is needed for a neuron to fire to get the signal out, you know that there needs to be sufficient energy to alert the brain. But how much is needed?
- In order for the neuron to fire, the all-or-none law is in place. There is an absolute threshold, the least amount of energy detected as stimulus 50% of time presented. So, 1 out of 2 times, you see the stimulus e.g. the light, the sound, the taste, etc. If the energy does not cross that absolute threshold, the energy will absolutely not be detected. On page 82, there is a listing of approximate absolute thresholds under ideal circumstances. Yet what about changes in stimulus? Ever watch a movie that goes quiet from a loud scene? When you reach for the remote to turn it up, how soon before you notice the difference? How much louder do you need it? The difference threshold is the smallest change in stimulation that can be detected 50% of the time. It varies according to the strength or intensity of the original stimulus. 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.
- Have you ever found yourself more or less vulnerable to stimuli? Like loud noises at the circus vs. a room of test takers? Adaptation is the adjustment of the senses to the level of stimulation they are receiving. We will discuss this principle with each sense. Think of it as adapting to the environment – you change your expectations and your experience changes. Honestly, I am not sure why the book manufacturer put the picture of this dude. I am not sure if they were applying that over time, one adapts to the pain of getting tattoos.
- Have you ever heard of songs or TV shows having subliminal messages in order to influence the consumer to do something? Beyond the conspiracy theory, there are some messages and marketing strategies to cause behavior through stimuli below the level of conscious awareness. There is a link explaining where the marketing strategy can from. Do subliminal messages influence behavior though? The evidence is the following: in a controlled laboratory setting, people can process and respond to information presented subliminally, but subliminal message outside the laboratory have no significant effect on behavior.
- Let’s get into the senses.
- Page 85 goes through how the visual system works. Here is a diagram depicting this process. The retina is the back lining of the eyeball and are where the receptor cells are located. They are sensitive to visible light only. 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).
- Rods and cones are the receptor cells. The cones allow for day vision and color whereas the rods allow for night vision. See the summary table for a description of the roles. 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.
- Again, adaptation is the process by which our senses adjust to the different levels of stimulation. How does it occur for vision? As the sensitivity of rods and cones changes according to how much light is available. It is like walking into a dark theatre on a bright sunny day. “Your eyes adjust” 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).
- Afterimage – sense experience that occurs after a visual stimulus has been removed. You will do this for your worksheet! You will also review blind spots.
- The optic nerve carries messages from each eye to the brain. See figure 3.9 on page 89 on how the optic nerves cross at the optic chiasm. Not all information goes to the occipital lobe although that is the main destination for registration and interpretation. The next slide goes through optical illusions. 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.
- I struggled with placement of this video. I want it to start the conversation about color but there are other topics we will reference back to later in the PowerPoint. Spinning diamond – spinning dancer
- See pages 89-91 on color discussing hues, brightness, and saturation. Great topics for those of you in photography! Because of saturation and brightness, the 150 hues we can see multiple colors seen to 2 million or more. The next video shows an artist using a device similar to the one Beau discussed to help overcome color blindness.
- Let’s transition into hearing.
- Sound – a psychological experience created by the brain in response to changes in air pressure that are received by the auditory system. It is our brain’s interpretation of the sensory information from the ear’s receptor cells of the vibrations. Sound Waves – changes in pressure caused when molecules of air or fluid collide with one another and then move apart again. How they are formed is reviewed on page 93. Frequency is also discussed. Pitch – auditory experience corresponding primarily to frequency of sound vibrations resulting in a higher or lower tone. 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.
- 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.
- 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 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.
- Why do you have to wear ear plugs in a factory? 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.). Wear ear plugs at home when operating this machinery! Hearing aids that utilize digital technology can enhance speech sounds while reducing background noise. There are interventions possible as stated on your screen. 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. Check out the focus book in the text on page 97. Do you believe intervention should be done?
- What other senses do we have?
- How humans smell remains an open question. We have 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. Pheromones – chemicals that communicate information to other organisms through smell. Your textbook has an interesting review of research on how pheromones allegedly influence human behavior and may influence sexual orientation? What are your thoughts? Adaptation occurs with smell as well.
- 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. Not the bumps!! 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. We have adaptation that occurs with taste.
- 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. Which way is up and which way is down. 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.
- 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. Touch is important for interaction and emotional experience.
- 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.
- Organizing and making sense! Gestalt researchers wanted to understand this further. The history of the Gestalt psychologists is available in your resources folder. There is also more explanation of their principles for perceptual organization.
- 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.
- One of the basic perceptual processes involves distinguishing the object of one’s attention (i.e.., the “figure”) from the background (i.e., “ground”). There is a video about attention at the end of this PowerPoint. . As seen in the picture with the Dalmatian, the figure must be noticeable enough to draw our attention. Figure with clear contours can be perceived in 2 very different ways. Check out Figure 3-26 and 3-27. Which is ground? Figure?
- Proximity – when objects are close to one another, we tend to perceive them together rather than separately. “The whole is greater than the sum of its parts”
- Similarity – objects that are of a similar color, size, or shape are usually perceived as part of a pattern.
- Closure – we are inclined to overlook incompleteness in sensory information and to perceive a whole object even when none really exists.
- Continuity – items that continue a pattern or direction tend to be grouped together as part of the pattern.
- 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.
- 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.
- 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. Check out the next two videos on the observer characteristics.
- Lecture/Discussion: Unattended Information and the “Cocktail Party Phenomenon” It has happened to all of us. You are at an office party, a holiday party, or a gathering of friends at the home of a neighbor; and you are engaged in conversation with a friend about the merits of Golden Retrievers compared to German Shepherds. More people are talking behind you, but you are not paying attention to their conversation. Suddenly, you hear your name mentioned by one of the individuals engaged in the conversation behind you. You become unable to concentrate on the puppy discussion, because you are too busy trying to hear what the other people are saying about you. You know you were not deliberately eavesdropping on this conversation, but you know that you heard your name. Is it possible that you were unconsciously eavesdropping? You have just experienced what Broadbent and Cherry referred to as the “Cocktail Party Phenomenon.” Part of consciousness is attention. We must attend to incoming stimuli in order to process it and act on it in an appropriate manner. Does that imply that in the case presented above, the listener was attending to the conversation behind her? Possibly, although the attention being paid to that conversation was not intentional. The listener in this conversation was engaged in what is known as dichotic listening, which refers to hearing two channels of sound, one in each ear, at the same time. In dichotic listening, we listen, or shadow, the message to which we are attending, and tune out the second, unattended message. Nonetheless, some characteristics of that unshadowed message still get through. The individual above was shadowing the message in which she was engaged and, until hearing her name, could not have told us the content or characteristics of the unshadowed (unattended) message of conversation. How then, did she manage to hear her name, if she was not attending to the message? Triesman offers as an explanation the fact that in dichotic listening, attention acts as an attenuator, in that it turns down the volume on unattended channels but does not completely block them out. Moray took this notion a bit further, observing that it is very difficult to ignore the sounds of our own names, even if that sound comes in on an unattended channel. Deutsch and Deutsch, followed by Norman, proposed that all channels that reach the system get some degree of attention and analysis. Specifically, the channels get attended to enough to be represented in long-term memory. While none of these models completely explains the attentional aspect of consciousness, they do at least give us some insights as to why we suddenly find ourselves “eavesdropping” on the conversations of others, once we have heard them mention our names.
- Instructor: Behind the little girl’s right shoulder, a black carousel horse appears and disappears.
- Instructor: The change in this slide appears on the left side. A smokestack appears and disappears.
- 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.