What is a manipulation check used for in experiments?

A manipulation check is a procedure used in experimental research to verify that the independent variable has been effectively manipulated and that the participants are experiencing the intended level of that variable. This process ensures that the changes in the dependent variable can be attributed to the manipulation of the independent variable rather than other factors.

In this context, verifying accurate creation of independent variable levels is crucial because it helps researchers confirm that differences observed in the experiment are genuinely due to the experimental conditions set by the independent variable. This validation is integral to the internal validity of an experiment, allowing researchers to draw clearer conclusions about cause-and-effect relationships.

The context of the other options helps to illuminate why they're not as applicable. While controlling all other variables is important in experiments, this describes a broader aspect of experimental design rather than a specific function of a manipulation check. Ensuring the realism of the environment is related more to ecological validity rather than directly checking the manipulation itself. Lastly, measuring participant biases pertains to ensuring that participants’ preconceptions or biases do not skew the results, which is a separate consideration from verifying how well the independent variable was manipulated.