1. Chapter 4 Sensation and Perception

2. Chapter 4 Overview 5 senses 5 senses Sensation processing Sensation processing How we see How we see

3. Chapter 4 Overview Depth Perception Depth Perception Color Perception Color Perception Organization of Sensory information Organization of Sensory information

4. Compensate for loss of senses Helen Keller  Deaf and Blind at 19 months old Helen Keller  Deaf and Blind at 19 months old Teacher was Anne Sullivan Teacher was Anne Sullivan –Taught her to speak –Taught her to listen to others –Keller and Sullivan later traveled the world speaking about their experiences

5. How Keller communicated… She used her other senses to communicate with other people

6. I. Understanding Sensation Sensation - the process by which our 5 senses gather information and send it to the brain Sensation - the process by which our 5 senses gather information and send it to the brain Stimulation of our senses is automatic Stimulation of our senses is automatic –You don’t decide when to see or hear things

7. I. Understanding Sensation Sensation can also be defined as: Sensation can also be defined as: – –The stimulation of sensory receptors and the transmission of sensory information to the central nervous system –CyberPsych, Virtual Reality and Vision Video CyberPsych, Virtual Reality and Vision VideoCyberPsych, Virtual Reality and Vision Video

8. I. Understanding Sensation Sensory Reduction  the process of selecting which sensory information is most important Sensory Reduction  the process of selecting which sensory information is most important –There is so much info received at the sensory receptors it is impossible to process it all –Sensory Reduction chooses what info gets processed and analyzed by the brain

9. I. Understanding Sensation Sensory Reduction takes place in the reticular activating system of the brain (Reticular Formation) Sensory Reduction takes place in the reticular activating system of the brain (Reticular Formation) Information is filtered during this process. Info will either stop here or continue for processing Information is filtered during this process. Info will either stop here or continue for processing

10. Diagram of what parts of the brain deal with which senses

11. I. Understanding Sensation Thresholds are very important to sensation within our body Thresholds are very important to sensation within our body There are two types of thresholds There are two types of thresholds 1. Absolute Threshold  1. Absolute Threshold  the weakest amount of a stimulus that can be sensed. This threshold differs from human to animals and from person to person

12. I. Understanding Sensation 2. Difference Threshold  2. Difference Threshold  The minimum amount of difference that can be detected between two stimuli People’s individual difference threshold may vary slightly People’s individual difference threshold may vary slightly Not as much as Absolute Threshold Not as much as Absolute Threshold

14. I. Understanding Sensation Sensory Adaptation  is the process by which we become more sensitive to weak stimuli and less sensitive to unchanging stimuli Sensory Adaptation  is the process by which we become more sensitive to weak stimuli and less sensitive to unchanging stimuli –Our sensory systems adapt to a changing environment –If our sensory systems could not change, we would not survive

15. I. Understanding Sensation Examples of Sensory Adaptation Examples of Sensory Adaptation –When your eyes adapt to the darkness –When people adapt to the sounds of city traffic Example of unchanging adaptation Example of unchanging adaptation –We do not usually adapt to pain

16. I. Understanding Sensation Signal – Detection Theory Signal – Detection Theory –Method of distinguishing sensory stimuli that takes into account not only the stimuli’s strengths but also such variables as: The setting The setting Your physical state Your physical state Your mood Your mood Your attitudes Your attitudes

17. I. Understanding Sensation Signal – Detection Theory Signal – Detection Theory –Theory also considers psychological factors such as: Motivations Motivations Expectations Expectations Learning Learning

18. Review 1) What is the process of selecting which sensory information is most important? ASensory Reduction ASensory Reduction BSensory Changing BSensory Changing CSensory Adaptation CSensory Adaptation DSensory Modality DSensory Modality 2) 2) The minimum amount of difference that can be detected between two stimuli is known as? ADifference Threshold BAbsolute Threshold CMinimum Threshold DMaximum Threshold

19. II. How we See and Hear Vision Vision –Light enters the eye, which relays information to the brain and allows us to see –People with normal color vision can see all colors in the spectrum of visible light –People who do not have normal color vision are said to be “color blind”

20. II. How we See and Hear Light Light –Electromagnetic energy described in wavelengths –Electromagnetic spectrum: light that is visible to humans and light that is not –The light that humans can see makes up only a small part of the spectrum –Colors of the spectrum are: –Red, Orange, Yellow, Green, Blue, Indigo, Violet

21. II. How we See and Hear Structures of the Eye Structures of the Eye –The pupil –The iris –The lens –The retina –Each part has a specific function regarding our vision

22. II. How we See and Hear Pupil  light enters the eye through the pupil Pupil  light enters the eye through the pupil Iris  dilates or constricts to vary the amount of light entering the eye Iris  dilates or constricts to vary the amount of light entering the eye Lens  clear, elastic structure that can change its shape to focus an image on the retina Lens  clear, elastic structure that can change its shape to focus an image on the retina Retina  back layer of the eye that contains visual receptor cells Retina  back layer of the eye that contains visual receptor cells

23. II. How we See and Hear Visual Receptor Cells Visual Receptor Cells –Called photoreceptors  these are the rods and cones –Rods  very sensitive to light and enable us to see at night –Cones  specialized for bright light conditions and enable us to see close and fine detail

24. II. How we See and Hear Dark Adaptation  Dark Adaptation  The adjustment to lower levels of light is called dark adaptation The ability to see in low light continues to improve for up to 45 minutes Bright Light Adaptation  occurs within a minute or two – –Adaptation to bright light happens much more quickly than adaptation to the dark

25. II. How we See and Hear  The sharpness of vision Visual Acuity  The sharpness of vision – –It is determined by the ability to see visual details in normal light – –Eye charts are used to measure visual acuity – –Nearsightedness, farsightedness

26. II. How we See and Hear Nearsightedness Nearsightedness –Caused by a longer than normal eyeball –Too sharply curved cornea Farsightedness Farsightedness –Caused by a shorter than normal eyeball Both are easily fixed with glasses Both are easily fixed with glasses

27. II. How we See and Hear The Color Wheel The Color Wheel – –The color wheel is made up of the colors of the spectrum bent into a circle – –Complementary colors are the colors across from each other on the color wheel – –When complementary colors of light mix, they form gray

29. II. How we See and Hear Hearing  Known as audition, detects sound waves, which result from rapid changes in air pressure caused by vibrating objects Hearing  Known as audition, detects sound waves, which result from rapid changes in air pressure caused by vibrating objects –Frequency of sound waves is measured in cycles per second and is sensed as the pitch of the sound –Hearing Video Clip Hearing Video ClipHearing Video Clip

30. II. How we See and Hear The amplitude of the sound is measured in decibels and is sensed as the loudness of the sound The amplitude of the sound is measured in decibels and is sensed as the loudness of the sound

31. II. How we See and Hear Structures of the ear Structures of the ear –Pinna  External, visible part of the ear –Eardrum  Tympanic membrane (vibrates when hit by sound waves) –Oval Window  Membrane separating the middle ear from the inner ear –Cochlea  Structure that forms the inner ear

32. II. How we See and Hear When parts of the ear are damaged, deafness can occur When parts of the ear are damaged, deafness can occur –Society has recently become more sensitive to the needs of deaf people through the use of the following: Interpreters Interpreters More courses in American Sign Language More courses in American Sign Language Advances in repairing damage inside the ear Advances in repairing damage inside the ear

33. Review 1) All of the following are structures of the eye except APupil APupil BIris BIris CLens CLens DKnee DKnee 2) Detection of sound waves from rapid changes in air pressure is known as what? ASight ASight BHearing BHearing CSmell CSmell DTouch DTouch

34. III. Other Senses Smell and Taste are known as chemical senses Smell and Taste are known as chemical senses –Very closely related to each other –Receptors for sense of smell are located in the top of the nasal cavity CyberPsych, Super Smellers Video CyberPsych, Super Smellers Video CyberPsych, Super Smellers Video CyberPsych, Super Smellers Video

35. III. Other Senses Smell Smell –People do not have as strong a sense of smell as many animals do –Odors are detected by receptor neurons in the nose Taste Taste –Most researchers agree on four basic taste qualities: sweet, sour, salty, and bitter –We sense taste through receptor neurons located on taste buds on the tongue

36. III. Other Senses Lock and Key Theory  relates to sense of smell Lock and Key Theory  relates to sense of smell –Humans can smell various odors because each three – dimensional odor molecule fits into only one type of receptor. –CyberPsych, Smart Nose Video CyberPsych, Smart Nose VideoCyberPsych, Smart Nose Video

37. III. Other Senses The Skin Senses The Skin Senses Pressure Pressure –The body is covered with hairs, some very tiny –Sensory receptors in the hair cells fire where the skin is touched –Other structures beneath the skin are also sensitive to pressure –The sense of pressure undergoes rapid adaptation

38. III. Other Senses The Skin Senses The Skin Senses Temperature Temperature –Sensations of temperature are relative –Neurons beneath the skin’s surface are receptors for temperature –As with the sense of pressure, people adapt rapidly to the sense of temperature

39. III. Other Senses The Skin Senses The Skin Senses Pain Pain –The more pain receptors located in a particular area, the more sensitive that area is –Pain moves from the point of contact to the spinal cord and then to the thalamus in the brain –It is then projected to the cerebral cortex, where the person registers the location and severity of the pain

41. III. Other Senses Body Senses Body Senses Vestibular Sense Vestibular Sense –Vestibular sense tells you whether you are physically upright without having to use your eyes –It works via sensory organs in the ear that monitor the body’s motion and position in relation to gravity

42. III. Other Senses Body Senses Body Senses Kinesthesis Kinesthesis –Kinesthesis is the sense that informs people about the position and motion of their bodies –It works via sensory organs in the joints, tendons, and muscles that send information to the brain

43. Review 1) The two senses that are very closely related are… ASmell and Sight ASmell and Sight BSmell and Hearing BSmell and Hearing CSmell and Taste CSmell and Taste DSight and Taste DSight and Taste 2) The sense that tells you whether you are physically upright without having to use your eyes is called what? AKinesthesis AKinesthesis BHearing BHearing CVision CVision DVestibular DVestibular

44. IV. Understanding Perception Perception  allows us to organize and make sense of our sensory impressions Perception  allows us to organize and make sense of our sensory impressions –Movement, depth, and constancy are some of the ways in which we make sense of these impressions –Cues help people perceive movement and motion and judge depth

45. IV. Understanding Perception Closure  The tendency to perceive a complete or whole figure even when there are gaps in what your senses tell you Closure  The tendency to perceive a complete or whole figure even when there are gaps in what your senses tell you It works when you try to fit pieces of information into a familiar pattern It works when you try to fit pieces of information into a familiar pattern

47. Do you see a cow??

48. How about now??

49. IV. Understanding Perception There are 4 forms of perception that will be discussed There are 4 forms of perception that will be discussed 1.Form perception 2.Perceptual Constancies 3.Depth Perception 4.Color Perception

50. IV. Understanding Perception 1)Form Perception  explores the following principles: 1)Form Perception  explores the following principles: –Figures –Proximity –Continuity –Closure –Similarity

51. IV. Understanding Perception 2)Perceptual Constancies includes information about the following: 2)Perceptual Constancies includes information about the following: –Size constancy – different objects are the same size no matter how far away –Shape constancy – one shape –Color constancy – objects keeping color in different light –Brightness constancy – equally bright

52. IV. Understanding Perception

53. 3)Depth Perception  There are two major types of cues for depth perception 3)Depth Perception  There are two major types of cues for depth perception –1) Binocular Cues  require two eyes to be perceived –2) Monocular Cues  require only one eye Monocular cues include perspective, clearness, overlap, shadow, and texture gradient

54. IV. Understanding Perception Depth Perception: ability to perceive three dimensional space and accurately judge distance

55. IV. Understanding Perception 4) Color Perception  Explained by a combination of two different theories 4) Color Perception  Explained by a combination of two different theories 1.Trichromatic Theory proposes that three kinds of color systems are maximally sensitive to blue, green and red. 2.Process Theory proposes each color is sensitive to two opposing colors which are blue and yellow, red and green, and black and white

56. IV. Understanding Perception Color Perception Color Perception –The trichromatic system operates at the level of the retina –The process system occurs at the level of the brain –The people who cannot perceive colors normally are considered color blind

57. Now, look at a few perception and organization objects

62. IV. Understanding Perception Interpretation: Final stage of perception Interpretation: Final stage of perception Interpretation is influenced by several factors including Interpretation is influenced by several factors including –Perceptual adaptation –Perceptual set –Individual motivation –Frame of reference

63. Review 1) All of the following are perceptual constancies except? AOverall Constancy AOverall Constancy BShape Constancy BShape Constancy CSize Constancy CSize Constancy DColor Constancy DColor Constancy 2) The tendency to perceive a complete or whole figure even when there are gaps in what your senses tell you is called what? AInterpretation AInterpretation BClosure BClosure CGap closing CGap closing DFigure constancy DFigure constancy