1. Chapter 4: Sensation and Perception
Psychology in Action (8e) by Karen Huffman
PowerPoint  Lecture Notes Presentation
Chapter 4: Sensation and Perception
Karen Huffman, Palomar College
©John Wiley & Sons, Inc Huffman: Psychology in Action (8e)

2. ©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)
Lecture Overview
Introduction to Sensation & Perception
Understanding Sensation
How We See and Hear
Our Other Senses
Understanding Perception
©John Wiley & Sons, Inc Huffman: Psychology in Action (8e)

3. Introduction to Sensation and Perception
Sensation (process of receiving, converting, and transmitting raw sensory information from the external and internal environments to the brain)
Perception (process of selecting, organizing, and interpreting sensory information)
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4. Sensation Versus Perception
When you stare at the cube on the left, which area is the top, bottom, or back?
In the figure on the right, is this a young woman looking to the right, or an older woman with her chin buried in her jacket?
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5. Sensation Vs. Perception
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6. Understanding Sensation: Processing
Processing (sensory organs contain receptors that receive sensory information from the environment)
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7. Understanding Sensation: Processing
Three Types of Processing:
Transduction converts the sensory stimuli into neural impulses that are sent on to the brain.
Sensory reduction filters and analyzes incoming sensations before sending on to the brain.
Coding converts particular sensory input into a specific sensation sent to parts of the brain.
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8. Understanding Sensation: Processing (Continued)
Transduction, sensory reduction, and coding all occur at the sensory level and messages are then sent on to the brain.
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9. Understanding Sensation: Thresholds
Psychophysics: Testing limits and changes
Absolute Threshold: smallest amount of a stimulus we can detect
Difference Threshold: minimal difference needed to detect a a stimulus change; also called the just noticeable difference (JND)
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10. Understanding Sensation: Thresholds
Sensory Adaptation: decreased sensory response to continuous stimulation
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11. ©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)
How We See
VISION- How We See
Light is a form of electromagnetic energy that moves in waves.
Many types of electromagnetic waves form the electromagnetic spectrum.
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12. How We See: Electromagnetic Spectrum
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13. How We See: Electromagnetic Spectrum
The flower on the left looks normal to us, whereas the one on the right was photographed under ultraviolet light.
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How We See: Light Waves
Light waves vary in:
length (wavelength), which determines frequency (hue or color).
height (amplitude), which determines brightness or intensity.
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15. How We See: Anatomy of the Eye
The function of the eye is to capture light waves and focus them on receptors at the back of the eyeball.
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16. How We See: Structures of the Retina
Receptors for vision are the rods and cones located in the retina.
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Do You Have a Blind Spot?
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18. How We See: Are You Nearsighted or Farsighted?
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How We Hear: Audition
Sound results from movement of air molecules in a particular wave pattern.
Sound waves vary in:
length (wavelength), which determines pitch (highness or lowness).
height (amplitude), which determines loudness (intensity of the sound).
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20. ©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)
How We Hear: Audition
The loudness of a sound is measured in decibels. Constant noise above 90 decibels can cause permanent nerve damage to the ear.
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21. How We Hear: Anatomy of the Ear
Receptors for hearing are hair cells located in the cochlea.
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22. ©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)
Our Other Senses
Our sense of smell is called olfaction.
Receptors for smell are embedded in a nasal membrane, the olfactory epithelium.
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23. Our Other Senses: Gustation (Sense of Taste)
Receptors for gustation are taste buds, located in the papillae on the surface of the tongue.
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24. Our Other Senses: Three Body Senses
Skin senses involve three basic skin sensations- touch (or pressure), temperature, and pain.
Receptors for these sensations occur in various concentrations and depths in the skin.
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25. Our Other Senses: Three Body Senses
Vestibular sense (or sense of balance) involves the vestibular sacs and semicircular canals located in the inner ear.
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26. Three Body Senses (Continued)
Kinesthesia provides the brain with information about bodily posture and bodily movement. Kinesthetic receptors are found throughout the muscles, joints, and tendons of the body.
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27. Understanding Perception
Illusions: false or misleading perceptions help scientists study the processes of perception (e.g., the horizontal-vertical illusion)
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Understanding Perception: The Muller-Lyer Illusion Which vertical line is longer?
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29. Understanding Perception
Do You See the Cow?
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30. Understanding Perception
Now Can You See the Cow?
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31. Understanding Perception (Continued)
Perception’s three basic processes:
Selection
Organization
Interpretation
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32. Understanding Perception: Selection
Selection (choosing where to direct attention) involves three factors:
Selective Attention (filtering out and attending only to important sensory messages)
Feature Detectors (specialized neurons respond only to certain sensory
information)
Habituation (brain’s tendency to ignore environmental factors that remain constant)
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33. Understanding Perception: Selection
Kittens raised with only vertical visual stimuli fail to develop the ability to detect horizontal lines. Can you explain why?
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34. Understanding Perception: Organization
Organization: assembling of information into patterns that help us understand the world
We organize sensory information in terms of:
Form
Constancy
Depth
Color
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35. Understanding Perception: Organization
Form Perception
Gestalt psychologists developed laws explaining how people perceive form according to:
Figure and ground
Proximity
Continuity
Closure
Similarity
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36. Form Perception- Basic Gestalt Principles
Understanding Perception: Organization
Form Perception- Basic Gestalt Principles
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37. Form Perception: Can You Explain These Impossible Figures?
Understanding Perception: Organization
Form Perception: Can You Explain These Impossible Figures?
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Understanding Perception: Organization
Perceptual Constancy: Tendency to perceive the environment as remaining the same even with changes in sensory input.
Four best-known constancies:
Size
Shape
Color
Brightness
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39. Can You Identify the Size, Shape, Color, and Brightness Constancies?
Understanding Perception: Organization
Can You Identify the Size, Shape, Color, and Brightness Constancies?
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Understanding Perception: Organization--
The Ames Room Illusion
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Understanding Perception: Organization
Depth Perception: ability to perceive three dimensional space and accurately judge distance
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42. ©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)
Understanding Perception: Organization
Depth Perception (Continued)
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43. ©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)
Understanding Perception: Organization
Depth Perception involves both binocular (two eyes) and monocular (one eye) cues.
Two Binocular Cues for Depth:
Retinal disparity (separation of the eyes causes different images to fall on each retina)
Convergence (the closer the object the more the eyes turn inward)
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44. Binocular Cues- Retinal Disparity (left) Convergence (right)
Understanding Perception: Organization
Binocular Cues- Retinal Disparity (left) Convergence (right)
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45. ©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)
Understanding Perception: Organization
Six Monocular Depth Cues: Can You Find Them?
linear perspective
interposition
relative size
texture gradient
aerial perspective
light and shadow
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46. ©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)
Understanding Perception: Organization
Color Perception is a combination of two theories:
Trichromatic: color perception results from mixing three distinct color systems (red, green, and blue)
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47. ©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)
Understanding Perception: Organization
Color Perception is a combination of two theories:
Opponent-process: color perception results from three systems of color opposites (blue-yellow, red-green, and black-white)
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48. ©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)
Understanding Perception: Organization
People who have red-green color deficiency have trouble perceiving the green colored number in the center of this circle.
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49. ©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)
Understanding Perception: Organization and Color Perception
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50. Understanding Perception: Four Factors in Interpretation
Interpretation (how we explain sensations) involves four major factors:
Perceptual adaptation (brain adapts to changed environments)
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51. ©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)
Understanding Perception: Four Factors in Interpretation
Perceptual set: readiness to perceive in a particular manner, based on expectations
Some groups are more likely than others to be affected by the center item in this collection. Can you explain why?
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52. ©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)
Understanding Perception: Four Factors in Interpretation
Another example of perceptual set. Do you notice anything wrong with these photos?
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53. ©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)
Understanding Perception: Four Factors in Interpretation
Frame of reference: based on the context of the situation
Bottom-up or top-down processing: information either starts with raw sensory data or with thoughts, expectations, and knowledge
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54. Problems with Believing in Subliminal Perception and ESP
Subliminal perception may occur, but there is little or no evidence of subliminal persuasion.
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55. Problems with Believing in Subliminal Perception and ESP
Extrasensory perception (ESP): supposed ability to perceive things that go beyond the five normal senses
ESP research is criticized due to lack of experimental control and replicability.
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56. Sensation and Perception
Psychology in Action (8e) by Karen Huffman
PowerPoint  Lecture Notes Presentation
End of Chapter 4:
Sensation and Perception
Karen Huffman, Palomar College
©John Wiley & Sons, Inc Huffman: Psychology in Action (8e)