A Level Psychology OCR Test 2026 – 400 Free Practice Questions to Pass the Exam

Experimental methods are distinguished by their involvement in manipulating a variable, typically referred to as the independent variable, to observe the effect on another variable, known as the dependent variable. This manipulation allows researchers to establish cause-and-effect relationships, which is a core strength of experimental designs. By controlling other variables and using random assignment to groups, experimenters can isolate the effects of the manipulated variable with greater confidence, thus contributing to the internal validity of the study.

In contrast, non-experimental methods do not involve the manipulation of independent variables. Instead, these methods often focus on observing relationships or correlations without attempting to influence those variables, making them better suited for descriptive studies or exploratory research. Non-experimental methods may include surveys, observational studies, and case studies. Therefore, the primary distinguishing characteristic of experimental methods is their active manipulation of variables, which sets them apart from non-experimental approaches in psychological research.