Example of an Experiment: Note-Taking Method and Learning Performance

Functional Relationship Between Independent and Dependent Variables

A researcher conducts a study to determine if the amount of sleep affects problem-solving skills. One group of participants is allowed to sleep for eight hours, while a second group is only allowed to sleep for four hours. The next morning, both groups are given the same set of puzzles to solve, and the researcher records how many puzzles each participant completes correctly. In this study, what is the independent variable?

Identifying Experimental Variables

Extraneous Variable

Treatment

Non-Experimental Research

Non-Manipulated Independent Variable

Operational Definition

Experimental Manipulation

Experimental Condition

Internal Validity

Manipulation Check

Null Result

In an experimental research study, how is an independent variable defined?

A researcher conducts an experiment to determine if a new cognitive exercise improves memory retention. They have one group practice the exercise daily while a second group does not, and then they measure both groups' memory test scores. In this study, the memory test scores represent the independent variable.

Match each psychology study description to the specific factor that serves as the independent variable in that research scenario.

A researcher is investigating how anxiety affects cognitive performance. Arrange the following methods of operationalizing the Independent Variable (IV) from the approach that provides the highest degree of internal validity (strongest causal evidence) to the approach that provides the lowest degree.

In a factorial research design investigating how both lighting conditions (bright vs. dim) and participant age (young vs. old) affect visual search speed, a researcher classifies both 'lighting' and 'age' as _____ variables because they are both hypothesized to be causes of the variation in search speed.

According to the definition of experimental research, what is the role of an independent variable in a cause-and-effect relationship?

True or False: In psychological research, an independent variable must always be manipulated by the researcher and can never simply be measured.

Match each research design scenario to the correct status of its independent variable (IV) based on the study's design.