Designing psychological research: 11.1.10 field experiment

The idea

A field experiment is conducted in a natural, everyday environment where the researcher deliberately manipulates the independent variable to measure its effect on the dependent variable. Because the setting is natural, such as a school or a high street, participants are often unaware they are in a study. This significantly reduces demand characteristics and increases ecological validity. For example, a researcher might drop a wallet in a shopping centre to test if the dropper's gender affects whether bystanders help. However, field experiments offer less control over extraneous variables, making it harder to establish a definitive cause-and-effect relationship and more difficult to replicate the study exactly.

What earns the marks

• Identify that a field experiment takes place in a natural, real-world setting.
• Recognise that the researcher still manipulates the independent variable.
• Explain that ecological validity is high because the environment reflects real life.
• Evaluate the method by noting the difficulty in controlling extraneous variables and replicating the study.

Common mistakes and how to put them right

• Confusing a field experiment with a natural experiment.

  Put it right: In a field experiment, the researcher manipulates the independent variable, whereas in a natural experiment, the independent variable changes naturally.

• Assuming field experiments have no control over variables.

  Put it right: While control is lower than in a laboratory, researchers still attempt to control the independent variable and measure the dependent variable systematically.

• Stating that participants always give informed consent.

  Put it right: Participants in field experiments are often unaware they are being studied, which raises ethical issues regarding consent and deception.

Exam tips

• Highlight the trade-off between high ecological validity and lower control over extraneous variables.
• Mention ethical considerations, such as lack of informed consent, when evaluating field experiments.
• Use real-world examples, like bystander intervention in a public place, to illustrate the natural setting.