1. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Psychology in Action, Fifth Edition by Karen Huffman, Mark Vernoy, and Judith Vernoy PowerPoint  Lecture Notes Presentation Chapter 3: Sensation and Perception Paul J. Wellman Texas A&M University

2. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Lecture Overview Experiencing Sensations Vision Other Senses Perception –Selection –Organization –Interpretation

3. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Sensation and Perception Sensation is the process of receiving, converting, and transmitting information from the outside world –Sensory organs contain receptors that transduce sensory energy into nerve impulses that are carried to the brain Perception involves organization and interpretation of sensory input

4. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Sensory Thresholds Each sense has a threshold level of energy required to activate that sense –Absolute threshold: The smallest amount of energy that can be detected –Difference threshold: The smallest difference in sensory energies that can be detected

5. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Vision External light falls on receptors within the eye to generate the visual message Light = electromagnetic radiation –Wavelength determines color

6. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Anatomy of the Eye

7. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Photoreceptors Photoreceptors are light sensitive cells found within the retina –Rods are sensitive to light but not color, are active under low-light conditions –Cones are sensitive to color, are not active in low-light conditions, allow for fine detail –Rods and cones use different photopigments that react to light so as to generate nerve potentials

8. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Retinal Photoreceptors

9. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Sensory Coding Activation of retinal cells by light results in action potentials that travel along neurons that project to the occipital cortex

10. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Hearing Receptors within the ear are tuned to detect sound waves (changes in sound pressure) –Sound waves show Frequency: corresponds to pitch Amplitude: corresponds to loudness Sound loudness is measured in decibels

11. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Sound Loudness (dB)

12. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Anatomy of the Ear (Sound Waves)

13. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Pitch and Loudness Sound waves vibrate the basilar membrane within the cochlea of the ear –Hair cells containing receptors bend in response to vibration of the membrane –Hair cells trigger action potentials that are carried to the auditory cortex –Different frequencies produce maximal vibration of different areas along the membrane: produces place coding of pitch

14. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Perception Sensation refers to detection and transduction of sensory stimuli Perceptual process include –Selection –Organization –Interpretation Perceptions may not match sensations –Illusions are an example

15. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Horizontal-Vertical Illusion WHICH LINE IS LONGER?

16. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Form Perception Figure and background are basic organizational themes for perception Gestalt psychologists examined properties that make for a good figure –Figure is perceived as distinct from the background –Figure is closer to the viewer than the background

17. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Gestalt Organizational Principles

18. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Color Perception Trichromatic theory –Eye contains 3 different color sensitive elements Blue, green or red elements Trichromatic theory accounts for color mixing of lights Opponent-Process theory –Visual system is organized into red-green, blue-yellow and black-white units Accounts for negative color afterimages

19. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Extrasensory Perception ESP refers to the ability to perceive stimuli that are outside the 5 senses –Telepathy: the ability to read minds –Clairvoyance: the ability to perceive objects or events –Precognition: the ability to predict the future –Psychokinesis: the ability to move objects

20. © 2000 John Wiley & Sons, Inc. Huffman/Vernoy/Vernoy: Psychology in Action 5e Copyright Copyright 2000 by John Wiley and Sons, New York, NY. All rights reserved. No part of the material protected by this copyright may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without written permission of the copyright owner.