CHAPTER 1: INTRODUCTION TO PERCEPTION

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

CHAPTER 1: INTRODUCTION TO PERCEPTION

Chapter Outline

• Introduction

A.Some Questions We Will Consider

1.Hypothetical “Science Project”: Design a Sensory Device

II.Why Read This Book?III.The Perceptual Process A.But What About “Sensation”?B.Distal and Proximal Stimuli (Steps 1 and 2) 1.Distal stimulus 2.Principle of transformation 3.Proximal stimulus 4.Principle of representation C.Receptor Processes (Step 3) 1.Sensory receptors

a.Example: visual pigment

2.Transduction

• Neural Processing (Step 4)

1.Transmission 2.Change/Processing Signal 3.Primary receiving area 4.Cerebral Cortex a.Occipital lobe b.Temporal lobe c.Parietal lobe d.Frontal lobe

• Behavioral Responses (Steps 5-7)

1.Perception 2.Recognition

a.Problems of recognition: e.g., visual form agnosia

3.Action E.Knowledge

1.Demonstration: perceiving a picture

a.The “Rat-Man” 2.Categorize 3.Bottom-up (data-based) processing 4.Top-down (knowledge-based) processing IV.Studying the Perceptual Process A.The Two “Stimulus” Relationships (A and B) 1.Stimulus-perception relationship Sensation and Perception 10e Bruce Goldstein, James Brockmole (Instructor's Manual All Chapters, 100% Original Verified, A+ Grade) (Lecture Notes Only) 1 / 4

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

2.Stimulus-physiology relationship B.The Physiology-Perception relationship C.Cognitive Influences on Perception

• “Test Yourself 1.1”

VI.Measuring Perception A.Gustav Fechner Introduces Methods to Measure Thresholds

1.Classical Psychophysical Methods:

a.Method of Limits i.Absolute Threshold ii.Difference Threshold 2.Five Questions About the Perceptual World

a.Question 1: What is the Perceptual Magnitude of a

Stimulus? Technique: Magnitude Estimation

b.Method: Magnitude Estimation

c.Question 2; What is the Identity of a Stimulus? Technique:

Recognition Testing d.Question 3: How Quickly Can I React to It? Technique: Reaction Time

e.Question 4: How Can I Describe What Is Out There?

Technique: Phenomenological Report

f.Question 5: How Can I Interact With It? Technique: Physical Tasks and Judgments VII.Something to Consider: Why is the Difference between Physical and Perceptual Important?VIII.“Test Yourself 1.2” IX.Think About It

• Key Terms

Learning Objectives

At the end of the chapter, the student should be able to:

1.State and explain each step of the perceptual process.

2.Differentiate between “top-down” and “bottom-up” processing.

3.Describe how cognitive processes can influence perception.

4.List five different ways to study perception.

5.Explain the concept of recognition and how it is distinct from perception.

6.Define “absolute threshold” and “difference threshold.” 7.Describe the methods used in method of limits and magnitude estimation studies. 2 / 4

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.Chapter Overview/ Summary

Chapter 1 introduces the student to the basic concepts in perception. The opening vignette engages the student to think about perception as a science project: how you design a device to obtain information from the environment. This exercise reveals some of the major issues and complexities in perception. Next, four reasons for studying perception are outlined: (1) studying perception can result in a career: (2) applications of perception research overlap with other fields, such as medicine (e.g., treating dysfunctions of sensory systems), robotics, computer science, and engineering; (3) studying perception results in a greater appreciation of your sensory systems and enhances your curiosity about perceptual experiences; and (4) studying perception is inherently interesting.Goldstein then presents the steps of the “perceptual process”. These steps can be included in four categories: (1) Stimuli; (2) Receptor Processes; (3) Neural Processing; (4) Behavioral Responses. The role of Knowledge is also discussed in relation to the steps of the perceptual process. The process starts with the environmental stimulus, followed by the stimulus on the receptors (the “image” in vision. Stimulus processing continues with transduction (converting the physical energy into neural energy); transmission (receptors activating other neurons, which activate more neurons); and neural processing (the interactions between neurons and neural systems). Transduction is analogous to information transmission between an individual and an ATM. The steps categorized as “Behavioral Responses” are: perception (the conscious sensory experience); recognition (classifying objects into categories); and action (motor activities that occur to react to the sensory information. The “Knowledge” section highlights the influence of “top-down” cognitive processes on other steps in the perceptual process, as shown by the “rat-man” demonstration. The remainder of the chapter addresses how perception is studied. The approaches to studying perception are the psychophysical level of analysis (the stimulus- perception relationship) and the physiological approach (the stimulus-physiology relationship and the physiology-perception relationship). Both approaches are necessary to fully understand perception. Cognitive influences on perception are also vitally important to study. More specific ways of studying the psychophysical level of analysis are then detailed. These include detection/measuring thresholds; magnitude estimation, description (phenomenological method), and various behavioral methods (visual search, same-different judgments, distance judgments). Classical psychophysical methods for measuring detection are the method of limits, method of adjustment, and the method of constant stimuli (the latter two discussed in Appendix A). Using these methods, a researcher can determine the participant’s absolute threshold and difference threshold (DL). ’s law is the first psychophysical law discussed in Appendix B: the ratio of the DL to the standard stimulus is a constant fraction. Magnitude estimation is also discussed in more detail in Appendix C, including the major method used, representative results from stimuli in different modalities, and Stevens’s Power Law. Results from judging the brightness of a light indicate “response compression” (doubling the physical intensity of the light less than doubles the perceptual brightness of the light). Results from judging the intensity of an electric shock indicate “response expansion” (doubling the physical intensity of the shock more than doubles the perceptual response to the shock). Stevens’s Power Law specifies the relationship between the physical intensity and the perceptual experience. A key component of this law is that the physical stimulus intensity is raised 3 / 4

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.to an exponent. This exponent is derived from the slope of the line created by taking the logarithm of the physical intensities and the logarithm of the magnitude estimations. The reason why it is a good thing for humans to have brightness show response compression, and electric shock show response expansion, is discussed. Appendix D introduces the idea of response criterion in a detection study, and how signal detection theory accounts for this.

Demonstrations, Activities, and Lecture Topics

(1) Inherent Interest in Perception: Encourage students to bring in examples of visual phenomena that they may have seen. Many students have had websites with illusions forwarded to them. Students may have 3-D magazines, books, or video games. I have an old box of Apple Jacks cereal that has numerous visual illusions on the back, and paper diner placemats with illusions. Emphasize the point that the ubiquity of these examples shows how inherently interesting perception is.

(2) Human Factors and Perception: Goldstein cites applications of perception as

one of the reasons for studying perception. A major contributor in this field is Donald Norman, the author of “The Psychology of Everyday Things” (1988), “Emotional Design” (2004), and “Living with Complexity” (2010). His JND (Just Noticeable Difference, a psychophysiological term related to difference thresholds) website has links to many of his essays and sample chapters (including “Attractive Things Work Better” from “Emotional Design” and “Memory is More Important than Actuality”). Two examples I like to use from “The Psychology of Everyday Things” are: (1) the beer-handle controls (Figure 4.6) to have visual and tactual discrimination of controls; and (2) the relatively well-known stove-top design and controls (Figures 3.3, 3.4 , and 3.5). The latter example shows the idea of natural mapping, which highlights the problem associated with the disputed “butterfly ballot” of the 2000 Presidential election.(Wikipedia provides a photo of the ballot and more information regarding its use in Florida). Goldstein also specifically mentions highway sign visibility. Don Meeker and James Montalbano have recently designed a new typeface for interstate highway signs; a slideshow of the development of this new typeface can be found at The New York Times website in a 2007 slideshow entitled “What’s Your Sign?”.

(3) “Do The Math” behind Stevens’s Power Law (Appendix C): Give your

students a concrete example of how Stevens’s Law works by plugging in actual values. To keep it simple, assume K=1. Then demonstrate response expansion by using n=3, and varying S from 2 to 8. Students will see how rapidly P increases.Then demonstrate response compression by using n=0.67 (or 2/3). This introduces the student to the wonderful world of fractional exponents, where you first square S, then take the cubed root of that quantity. Again, varying S from 2 to 8, the student will see that P does increase, but at a slower rate.

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