Psychology Research Methods

Welcome to Psychology Research Methods!  Created by The Research Methods Teaching and Learning Group This open education resource has been created for the use of PSY 321: Research Methods in Psychology at Portland State University.  This will serve as your reading for PSY 321 this quarter. The primary purpose of PSY 321: Research Methods in Read more »

Chapter I American Psychological Association. (2011). About APA. Retrieved from http://www.apa.org/about Bushman, B. J. (2002). Does venting anger feed or extinguish the flame? Catharsis, rumination, distraction, anger, and aggressive responding. Personality and Social Psychology Bulletin, 28, 724–731. Gilovich, T. (1991). How we know what isn’t so: The fallibility of human reason in everyday lif…

Key Takeaways Null hypothesis testing is a formal approach to deciding whether a statistical relationship in a sample reflects a real relationship in the population or is just due to chance. The logic of null hypothesis testing involves assuming that the null hypothesis is true, finding how likely the sample result would be if this Read more »

Key Takeaways Every variable has a distribution—a way that the scores are distributed across the levels. The distribution can be described using a frequency table and histogram. It can also be described in words in terms of its shape, including whether it is unimodal or bimodal, and whether it is symmetrical or skewed. The central Read more »

Key Takeaways APA style is a set of guidelines for writing in psychology. It is the genre of writing that psychologists use to communicate about their research with other researchers and practitioners. APA style can be seen as having three levels. There is the organization of a research article, the high-level style that includes writing Read more »

Key Takeaways Single-subject research—which involves testing a small number of participants and focusing intensively on the behavior of each individual—is an important alternative to group research in psychology. Single-subject studies must be distinguished from qualitative research on a single person or small number of individuals. Unlike more qualitative research, single-subject research focuse…

Key Takeaways Researchers often include multiple independent variables in their experiments. The most common approach is the factorial design, in which each level of one independent variable is combined with each level of the others to create all possible conditions. Each independent variable can be manipulated between-subjects or within-subjects. Non-manipulated independent variables (gender) ca…

Key Takeaways Quasi-experimental research involves the manipulation of an independent variable without the random assignment of participants to conditions or counterbalancing of orders of conditions. There are three types of quasi-experimental designs that are within-subjects in nature. These are the one-group posttest only design, the one-group pretest-posttest design, and the interrupted time-s…

Key Takeaways Survey research features the use of self-report measures on carefully selected samples. It is a flexible approach that can be used to study a wide variety of basic and applied research questions. Survey research has its roots in applied social research, market research, and election polling. It has since become an important Read more »

Key Takeaways Non-experimental research is research that lacks the manipulation of an independent variable. There are two broad types of non-experimental research. Correlational research that focuses on statistical relationships between variables that are measured but not manipulated; and observational research in which participants are observed and their behavior is recorded without the research…

Key Takeaways An experiment is a type of empirical study that features the manipulation of an independent variable, the measurement of a dependent variable, and control of extraneous variables. An extraneous variable is any variable other than the independent and dependent variables. A confound is an extraneous variable that varies systematically with the independent variable. Read more »

Key Takeaways An experiment is a type of empirical study that features the manipulation of an independent variable, the measurement of a dependent variable, and control of extraneous variables. An extraneous variable is any variable other than the independent and dependent variables. A confound is an extraneous variable that varies systematically with the independent variable. Read more »

Key Takeaways Measurement is the assignment of scores to individuals so that the scores represent some characteristic of the individuals. Psychological measurement can be achieved in a wide variety of ways, including self-report, behavioral, and physiological measures. Psychological constructs such as intelligence, self-esteem, and depression are variables that are not directly observable because…

Key Takeaways A wide variety of ethical issues arise in psychological research. Thinking them through requires considering how each of four moral principles (weighing risks against benefits, acting responsibly and with integrity, seeking justice, and respecting people’s rights and dignity) applies to each of three groups of people (research participants, science, and society). Ethical Read more »

Key Takeaways Research in psychology can be described by a simple cyclical model. A research question based on the research literature leads to an empirical study, the results of which are published and become part of the research literature. The research literature in psychology is all the published research in psychology, consisting primarily of articles Read more »

Key Takeaways Knowledge is acquired in many ways including intuition, authority, rationalism, empiricism, and the scientific method Science is a general way of understanding the natural world. Its three fundamental features are systematic empiricism, empirical questions, and public knowledge. Psychology is a science because it takes the scientific approach to understanding human behavior. Pseudos…

Learning Objectives Conduct and interpret one-sample, dependent-samples, and independent-samples t- tests. Interpret the results of one-way, repeated measures, and factorial ANOVAs. Conduct and interpret null hypothesis tests of Pearson’s r.   In this section, we look at several common null hypothesis testing procedures. The emphasis here is on providing enough information to allow you to conduct…

Learning Objectives Explain the purpose of null hypothesis testing, including the role of sampling error. Describe the basic logic of null hypothesis testing. Describe the role of relationship strength and sample size in determining statistical significance and make reasonable judgments about statistical significance based on these two factors.  The Purpose of Null Hypothesis Testing As Read more…

Learning Objectives Describe what is meant by the “replicability crisis” in psychology. Describe some questionable research practices. Identify some ways in which scientific rigor may be increased. Understand the importance of openness in psychological science.   At the start of this book we discussed the “Many Labs Replication Project,” which failed to replicate the original finding by Simone Re…

Learning Objectives Define Type I and Type II errors, explain why they occur, and identify some steps that can be taken to minimize their likelihood. Define statistical power, explain its role in the planning of new studies, and use online tools to compute the statistical power of simple research designs. List some criticisms of conventional Read more »