Research Methods in Psychology

Research Claims

• Frequency Claims: Describe the rate or amount of a certain variable. Examples include the percentage of students who get stressed during their first semester, or the percentage who sleep less than six hours before exams.

• Association Claims: Explore the relationship between two variables. A positive or negative correlation is measured. These relationships can be shown using scatter plots. Examples include the link between temperature and coffee sales, or whether coffee sales increase when the temperature goes down.

• Causal Claims: Assert that one variable causes changes in another. This requires experimental research, isolating the independent variable and dependent variable, and randomly assigning participants. An example would be how caffeine impacts memory performance.

Research Validity

• Construct Validity: Ensures the variables being measured accurately reflect the intended concepts. A valid operational definition is critical for this aspect.

• Internal Validity: Addresses if the study design rules out alternative explanations, particularly needed when making causal claims.

• External Validity: Deals with how generalizable the findings are to other situations and people.

• Statistical Validity: Assesses the strength of the relationship between variables and whether the observed effects are real and not due to chance.

• Frequency Claims: Require evaluating construct validity, external validity, and statistical validity.

• Association Claims: Require similar consideration of construct, external and statistical validity.

• Causal Claims: Demand all four types of validity for a strong study.

Research Variables

• Measured Variables: Observed and recorded as they naturally occur, such as hair color, IQ, or note-taking behavior.

• Manipulated Variables: Researchers control these, setting different levels or conditions. Researchers actively assign participants to groups. An example would be assigning participants to different treatment groups in an experiment.

• Variable Attributes: Some variables can only be measured due to inherent characteristics or limitations such as pre-existing conditions (eye color, nationality), ethical concerns, or sensitive personal attributes (IQ, religious beliefs).

Defining Variables

• Construct (Conceptual) Variable: The broader idea or concept being studied, like "multitasking."

• Conceptual Definition: A detailed explanation of the concept, such as what "preference for completing tasks" in the context of a study on multitasking.

• Operational Definition: A specific measurement method; ways to measure achievement in a study, such as self-reported grades, official school records, GPA, or teacher observations.

Important Research Considerations

• Not all validity types are needed in every research study; the goals dictate which ones are most critical.

• Maintaining external and internal validity can involve trade-offs.

• Operational definitions must align perfectly with the way variables are measured.

• Researchers must consider the ethical issues in choosing variables to be studied.