Throughout this book, you will read about amazing psychological science discoveries. But how do we know fact from fiction? How do psychological scientists choose research methods and design their studies in ways that provide meaningful results? Understanding how research is done—how testable questions are developed and studied—is key to appreciating all of psychology. Table 7.1 compares the features of psychology’s main research methods. In later modules, you will read about other research designs, including twin studies (Module 14) and cross-sectional and longitudinal research (Module 54).
| Research Method | Basic Purpose | How Conducted | What Is Manipulated | Weaknesses |
|---|---|---|---|---|
| Descriptive | To observe and record behavior | Do case studies, naturalistic observations, or surveys | Nothing | No control of variables; single cases may be misleading |
| Correlational | To detect naturally occurring relationships; to assess how well one variable predicts another | Collect data on two or more variables; no manipulation | Nothing | Cannot specify cause and effect |
| Experimental | To explore cause and effect | Manipulate one or more factors; use random assignment | The independent variable(s) | Sometimes not feasible; results may not generalize to other contexts; not ethical to manipulate certain variables |
In psychological research, no questions are off limits, except untestable (or unethical) ones: Does free will exist? Are people born evil? Is there an afterlife? Psychologists can’t test those questions. But they can test whether free will beliefs, aggressive personalities, and a belief in life after death influence how people think, feel, and act (Dechesne et al., 2003; Shariff et al., 2014; Webster et al., 2014).
Having chosen their question, psychologists then select the most appropriate research design—experimental, correlational, case study, naturalistic observation, twin study, longitudinal, or cross-sectional—and determine how to set it up most effectively. They consider how much money and time are available, ethical issues, and other limitations. For example, it wouldn’t be ethical for a researcher studying child development to use the experimental method and randomly assign children to loving versus punishing homes.
Next, psychological scientists decide on an operational definition—how to measure the behavior or mental process being studied. For example, researchers could measure aggressive behavior by measuring participants’ willingness to blast a stranger with supposed intense noise.
Researchers want to have confidence in their findings, so they carefully consider confounding variables—factors other than those being studied that may affect their interpretation of results.
Psychological research is a creative adventure. Researchers design each study, measure target behaviors, interpret results, and learn more about the fascinating world of behavior and mental processes along the way.