Research Methods: Experimental Design

Research methods form the foundation of psychology as a science. To test hypotheses, establish cause-and-effect relationships, and generate reliable findings, psychologists must design studies carefully. The experimental method is the most powerful tool for establishing causation because it allows the researcher to manipulate one variable and measure its effect on another while controlling extraneous variables.

Key Definition: An experiment is a research method in which the researcher manipulates an independent variable (IV), measures a dependent variable (DV), and controls extraneous variables to establish a cause-and-effect relationship.

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Key Terms in Experimental Design