Marcus conducted an experiment to investigate whether caffeinated energy drinks affect short-term memory recall. He asked a group of participants to consume a sugar-free energy drink containing 100mg of caffeine, wait 30 minutes, and then complete a digit-span recall task. One week later, the same participants were asked to consume an identical-tasting caffeine-free placebo drink, wait 30 minutes, and then complete an equivalent digit-span recall task.
Identify the independent variable (IV) in this experiment.
Practise Edexcel A Level Psychology Research methods and skills with exam-style questions for A Level Psychology. 657 questions covering Research methods and skills, matched to the Edexcel A Level Psychology (9PS0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
