A Level Psychology OCR Practice Exam

The answer is correct because field experiments typically lack the strict control over variables that laboratory experiments offer. In a field experiment, the research takes place in a natural environment where conditions are more variable and less predictable than in a controlled setting. This can lead to challenges in controlling extraneous variables that might affect the outcome of the study.

Greater control over variables would represent a strength of laboratory experiments, not field experiments. Field studies are often more ecologically valid because they involve real-world settings, but this comes at the cost of standardization and control over conditions.

The other choices reflect genuine disadvantages of field experiments: no standardization means that each instance of the experiment might yield different conditions; difficult replication denotes that, due to variable external factors, repeating a field experiment can be problematic; and causation uncertainty arises because the natural setting can introduce confounding variables that make it harder to establish direct cause-and-effect relationships. Thus, the assertion that greater control is a disadvantage is misplaced, highlighting why it stands as the correct answer to the question.