A researcher is planning a laboratory experiment to investigate the effect of a low-glycaemic diet versus a high-glycaemic diet (IVIVIV) on cognitive processing speed (DVDVDV). The researcher identifies that 'participants' baseline caffeine consumption' on the morning of the test is a major potential confounding variable.
Which of the following actions is most desirable for the researcher to plan in order to address this potential confounding variable and ensure high internal validity?
Document participants' caffeine intake post-hoc to retrospectively explain any outlying cognitive speed scores.
Control the variable by requiring all participants to abstain from caffeine for 12 hours prior to testing.
Tolerate the variable to maintain high ecological validity, allowing participants to consume caffeine as they normally would.
Ignore the variable under the assumption that caffeine's effect on processing speed is negligible.
201 exam-style questions on OCR A Level Psychology Planning and conducting research. Each one has a worked solution and a mark scheme showing where the marks go.