Research methods in psychology morling pdf download

THIRD EDITION

Research Methods in Psychology EVALUATING A WORLD OF INFORMATION

THIRD EDITION

Research Methods in Psychology EVALUATING A WORLD OF INFORMATION

Beth Morling UNIVERSITY OF DELAWARE

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Library of Congress Cataloging-in-Publication Data

Names: Morling, Beth, author. Title: Research methods in psychology : evaluating a world of information / Beth Morling, University of Delaware. Description: Third Edition. | New York : W. W. Norton & Company, [2017] | Revised edition of the author’s Research methods in psychology, [2015] | Includes bibliographical references and index. Identifiers: LCCN 2017030401 | ISBN 9780393617542 (pbk.) Subjects: LCSH: Psychology—Research—Methodology—Textbooks. | Psychology, Experimental—Textbooks. Classification: LCC BF76.5 .M667 2017 | DDC 150.72—dc23 LC record available at https://lccn.loc.gov/2017030401

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For my parents

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Brief Contents

PART I Introduction to Scientific Reasoning CHAPTER 1 Psychology Is a Way of Thinking 5

CHAPTER 2 Sources of Information: Why Research Is Best and How to Find It 25

CHAPTER 3 Three Claims, Four Validities: Interrogation Tools for Consumers of Research 57

PART II Research Foundations for Any Claim CHAPTER 4 Ethical Guidelines for Psychology Research 89

CHAPTER 5 Identifying Good Measurement 117

PART III Tools for Evaluating Frequency Claims CHAPTER 6 Surveys and Observations: Describing What People Do 153

CHAPTER 7 Sampling: Estimating the Frequency of Behaviors and Beliefs 179

PART IV Tools for Evaluating Association Claims CHAPTER 8 Bivariate Correlational Research 203

CHAPTER 9 Multivariate Correlational Research 237

PART V Tools for Evaluating Causal Claims CHAPTER 10 Introduction to Simple Experiments 273

CHAPTER 11 More on Experiments: Confounding and Obscuring Variables 311

CHAPTER 12 Experiments with More Than One Independent Variable 351

PART VI Balancing Research Priorities CHAPTER 13 Quasi-Experiments and Small-N Designs 389

CHAPTER 14 Replication, Generalization, and the Real World 425

Statistics Review Descriptive Statistics 457

Statistics Review Inferential Statistics 479

Presenting Results APA-Style Reports and Conference Posters 505

Appendix A Random Numbers and How to Use Them 545

Appendix B Statistical Tables 551

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BETH MORLING is Professor of Psychology at the University of Delaware. She attended Carleton College in Northfield, Minnesota, and received her Ph.D. from the University of Massachusetts at Amherst. Before coming to Delaware, she held positions at Union College (New York) and Muhlenberg College (Pennsylvania). In addition to teaching research methods at Delaware almost every semester, she also teaches undergraduate cultural psychology, a seminar on the self- concept, and a graduate course in the teaching of psychology. Her research in the area of cultural psychology explores how cultural practices shape people’s motivations. Dr. Morling has been a Fulbright scholar in Kyoto, Japan, and was the Delaware State Professor of the Year (2014), an award from the Council for Advancement and Support of Education (CASE) and the Carnegie Foundation for the Advancement of Teaching.

About the Author

ix

Preface

Students in the psychology major plan to pursue a tremendous variety of careers— not just becoming psychology researchers. So they sometimes ask: Why do we need to study research methods when we want to be therapists, social workers, teachers, lawyers, or physicians? Indeed, many students anticipate that research methods will be “dry,” “boring,” and irrelevant to their future goals. This book was written with these very students in mind—students who are taking their first course in research methods (usually sophomores) and who plan to pursue a wide variety of careers. Most of the students who take the course will never become researchers themselves, but they can learn to systematically navigate the research information they will encounter in empirical journal articles as well as in online magazines, print sources, blogs, and tweets.

I used to tell students that by conducting their own research, they would be able to read and apply research later, in their chosen careers. But the literature on learning transfer leads me to believe that the skills involved in designing one’s own studies will not easily transfer to understanding and critically assessing studies done by others. If we want students to assess how well a study supports its claims, we have to teach them to assess research. That is the approach this book takes.

Students Can Develop Research Consumer Skills To be a systematic consumer of research, students need to know what to priori- tize when assessing a study. Sometimes random samples matter, and sometimes they do not. Sometimes we ask about random assignment and confounds, and sometimes we do not. Students benefit from having a set of systematic steps to help them prioritize their questioning when they interrogate quantitative infor- mation. To provide that, this book presents a framework of three claims and four validities, introduced in Chapter 3. One axis of the framework is the three kinds of claims researchers (as well as journalists, bloggers, and commentators) might make: frequency claims (some percentage of people do X), association claims (X is associated with Y), and causal claims (X changes Y). The second axis of

x PREfACE

the framework is the four validities that are generally agreed upon by methodol- ogists: internal, external, construct, and statistical.

The three claims, four validities framework provides a scaffold that is rein- forced throughout. The book shows how almost every term, technique, and piece of information fits into the basic framework.

The framework also helps students set priorities when evaluating a study. Good quantitative reasoners prioritize different validity questions depending on the claim. For example, for a frequency claim, we should ask about measurement (construct validity) and sampling techniques (external validity), but not about ran- dom assignment or confounds, because the claim is not a causal one. For a causal claim, we prioritize internal validity and construct validity, but external validity is generally less important.

Through engagement with a consumer-focused research methods course, students become systematic interrogators. They start to ask more appropriate and refined questions about a study. By the end of the course, students can clearly explain why a causal claim needs an experiment to support it. They know how to evaluate whether a variable has been measured well. They know when it’s appro- priate to call for more participants in a study. And they can explain when a study must have a representative sample and when such a sample is not needed.