Experimental Design in Psychology

A Case Approach

M. Kimberly MacLin

• Publisher: Routledge
• Year: 2020
• ISBN:
  9781000727906
• Edition: 9
• Topic: Psicologia
• Subtopic: Psicologia sperimentale

This text is about doing science and the active process of reading, learning, thinking, generating ideas, designing experiments, and the logistics surrounding each step of the research process. In easy-to-read, conversational language, Kim MacLin teaches students experimental design principles and techniques using a tutorial approach in which students read, critique, and analyze over 75 actual experiments from every major area of psychology. She provides them with real-world information about how science in psychology is conducted and how they can participate.

Recognizing that students come to an experimental design course with their own interests and perspectives, MacLin covers many subdisciplines of psychology throughout the text, including IO psychology, child psychology, social psychology, behavioral psychology, cognitive psychology, clinical psychology, health psychology, educational/school psychology, legal psychology, and personality psychology, among others. Part I of the text is content oriented and provides an overview of the principles of experimental design. Part II contains annotated research articles for students to read and analyze. Classic articles have been retained and 11 new ones have been added, featuring contemporary case studies, information on the Open Science movement, expanded coverage on ethics in research, and a greater focus on becoming a better writer, clarity and precision in writing, and reducing bias in language.

This edition is up to date with the latest APA Publication Manual (7th edition) and includes an overview of the updated bias-free language guidelines, the use of singular "they, " the new ethical compliance checklist, and other key changes in APA style. This text is essential reading for students and researchers interested in and studying experimental design in psychology.

PART I

Basic Principles in Experimental Design

Some people dread taking the research methods course required for most psychology majors. I’m not sure of all the reasons why, but for many they fear the course. It often has a lab component; at some universities it is worth more credit than regular content courses. It simply often has the reputation of being “hard.” Instead, for a moment, consider that research methods is exciting! It provides you the tools to be able to conduct your own research. Finally, you are in charge and you can study what you want to know. You are explorer, scientist, puzzle solver.

The first half of this book (Part I) introduces to you the basics of scientific inquiry, including what science is and how psychological science is a subset of it. We’ll discuss how to distinguish between facts, theories, and speculation and how each are useful for developing research questions. We’ll cover the basics of the scientific method, the specifics of experimental design, and a review of other non-experimental research methods (so you know when it is appropriate to choose the experiment). You will be given insight into how to find and read the literature in psychology as well as how to plan, design, and carry out research. We will also cover the rules and procedures designed to ensure sound, ethical, and meaningful research. Throughout this material, you’ll be exposed to examples from the psychological literature that will allow you to see concepts and principles as they play out in real research studies. And in one particular chapter (Chapter 7) you’ll be prompted to critically analyze experimental designs that have conceptual or technical flaws. Being sensitive to mistakes will help you avoid them yourself.

Chapter 1

An Introduction to Scientific Inquiry

Every discipline has a way of knowing; a way of discovering new information and exploring and understanding information. Science is one way of knowing. Is psychology a science? Are psychology and science incongruent terms? It seems that psychology has lived in the shadow of “real” science for so long that many still believe it is a “soft” science, with little in common with the “hard” sciences like chemistry, physics, and biology. Science though is characterized by its method, not by its subject matter. Science is something you do. Similar to chemistry, physics, and biology, psychology has a laboratory tradition, with equipment, experimental techniques, and statistical analyses of data, upon which conclusions are based. The topics of psychology vary greatly, but systematic and experimental inquiry is what separates psychology from philosophy, lay opinion, armchair theorizing, and mindless meme-forwarding.

Presently, the experimental investigation of thought and behavior by psychologists follows the basic principles of scientific inquiry prescribed in other fields of science. While the things psychologists study (thought and behavior) distinguish psychology from other scientific fields, the method of inquiry is similar.

The Topics of Experimental Design

Experimental psychologists study a wide range of phenomena. Remember your introduction to psychology course? Each of those chapters (Biological Psychology, Social Psychology, etc.) cover the main content areas in psychology, with even the smallest topic in each chapter representing the research, and often life’s work, of many scientists. Psychological scientists study a myriad of topics, including the physiological components of emotion, eating behaviors of people in fast-food restaurants, poetry learning, the interpersonal relations between people of different status, the predatory behavior of the barn owl, the eye movements of newborn children, personality traits, the etiology of schizophrenia, brain patterns of people solving logic problems, and the attractiveness of average faces. These topics, and many, many more, are explored by researchers using experimental methods. In this book, you will be exposed to examples of many different research topics from all areas of psychology.

Regular people in their everyday lives frequently ponder these and other topics using speculation, subjective arguments, and personal experiences. These nonscientific interpretations, although sometimes interesting, are frequently unreliable and may lead to invalid conclusions (though our own personal experiences can lead us into general research areas and to specific research questions). So, for example, you’ve been sort of curious about the best way to approach someone who you are romantically interested in. Can this passing thought be studied experimentally? In fact, it can. Opening conversations have been the focus of research conducted by Kleinke, Meeker, and Staneski (1986), and Cunningham (1988). In one survey Kleinke et al. had research participants rate opening lines such as, “Isn’t it cold? Let’s make some body heat”; “Are you a student?”; and “I’m sort of shy, but I’d like to get to know you.” These lines were conceptualized to represent three different types of social advances: cute-flippant, innocuous, and direct. Overall, respondents agreed that cute-flippant opening lines were the least desirable.

With these data, Cunningham (1988) field-tested the opening lines by having researchers approach members of the opposite sex and begin a conversation in a bar with different types of social advances. In general, women reacted negatively to the cute-flippant lines and were positive to direct or innocuous opening lines. The reaction of men was ambiguous. Perhaps female-initiated conversation, no matter how innocuous or cute, is perceived by men as positive. The research illustrates that even cheesy pick-up lines can be analyzed experimentally.

CASE STUDY

Cognitive Psychology | Face Processing

Solso had long been interested in the arts, and as a cognitive psychologist, had interest in the brain and its workings. He was able to use his knowledge and skills as a scientist to scientifically study a topic that interested him: art and artists (a great example of using personal interests in a research career). Solso (2001) was interested in which brain processes were different among expert artists and non-artists. Using functional Magnetic Resonance Imaging (fMRI), Solso conducted brain scans of an artist and a non-artist while they sketched geometric forms and photographs of faces. The scans showed that there was an increase in blood flow to the areas of the brain responsible for face processing for both the artist and non-artist. But, while blood flow was elevated for both, the artist did not have as high a level of activation compared with the non-artist, indicating that the artist may process face information more efficiently (and thus, the brain might not need as much blood flow to that area to function). Additionally, this part of the brain (the right-posterior parietal region) was only activated when the research participants were drawing the faces, not when they were drawing the geometric forms. Furthermore, the artist showed greater activity in the right frontal area of the brain, which Solso inferred to mean that the “artist thinks portraits more than sees them” (Solso, 2001, p. 34).

So yes, it is possible to examine a wide variety of human thought and behavior scientifically; in other words, they may be subjected to analysis that follows a prescribed method of investigation in which the conclusions are reliable and valid. These terms, reliability and validity, have specialized meaning in psychological science. Reliability refers to the consistency of an experiment, test measurement, or observation. Thus, an experimenter may observe a certain action under specified conditions but, in order for the observation to be reliable, the same or other experimenters must be able to replicate the observation. Validity, on the other hand, is related to the factual accuracy of an observation test, or measurement. If, for example, you develop a test of intelligence and purport such a test will predict success in school, then the degree to which the test accurately predicts such results is called its validity. Validity refers to many types of observations and conclusions in psychological science in addition to tests. Take a bathroom scale. You step on the scale and it says you weigh 165 pounds. Is that number reliable? Assuming no weight loss or gain, if you step on the scale every day at the same time and it says you weigh 165 pounds, then you have a reliable scale. Is that number valid? One would need to verify that the scale is accurately measuring a known object with a weight of 165 pounds, such that anytime anything that is 165 pounds is placed on that scale, 165 is the readout. A scale needs to be reliable and valid for you to have faith in its measurements and for its data to have meaning. If you step on the scale every day at the same time (and at the same weight) and get a different answer, then the scale is not reliable, and the number is meaningless. The conclusions a scientist makes about their observations are based both on the reliability and validity of an experiment; they are both integral to the conduct of good science. Studying something scientifically allows you to yield reliable and valid conclusions about a wide range of behavior and thoughts. Indeed, the more seemingly bizarre the subject matter, the more rigorous psychologists must be in their application of experimental techniques.

What is Science?

If students are asked, “What is science?” many answer by giving examples of science: physics, chemistry, biology, and so on. This definition suggests that science is a generic term describing specific subject areas. For example, college students are required to take a number of “science” courses and these courses usually are drawn from physics, chemistry, astronomy, botany, biology, and the like. While some support for this definition can be found, it is less than specific and does not appear to be adequate. If you ask why chemistry is a science but history is not, or why physics is a science but music is not, the definition of science becomes more complex and usually confusing. People often argue that science deals with facts (yes, but so does history), or that science deals with theories (yes, but so does music), or that it involves...