Which of the following is an example of a laboratory experiment?

A laboratory experiment is characterized by its controlled environment where variables can be manipulated to observe their effects on dependent variables. In the context of Philip Zimbardo's Stanford Prison experiment, while this study took place in a simulated prison setting, it involved structured conditions where the environment and roles of participants were carefully arranged by the researchers. This allowed for the systematic investigation of how situational factors can influence behavior, which aligns with the principles of a laboratory experiment.

The other options do not fulfill the criteria for laboratory experiments: Jane Elliot's racism study is more of a field experiment focused on prejudice in a classroom setting; observational studies focus on naturally occurring behaviors without manipulation of variables; and the General Household Survey involves collecting data from a population without any experimental manipulation. These studies do not take place in a controlled setting or do not involve the systematic manipulation of independent variables, which is a hallmark of laboratory experiments.