A manufacturer claims that their new herbal energy shot, "FocusFlow", significantly improves cognitive concentration. To test this claim, a researcher recruits 40 students from a local college.
On the day of the trial, the students who volunteered to drink "FocusFlow" are given a 100 ml bottle of the active drink in the college library at 9:00 AM. Those who did not volunteer to drink it are assigned to the control group and given nothing.
At 10:00 AM, all 40 students are gathered in a computer lab to complete a computerized concentration and reaction-time test. The researcher, who developed the FocusFlow formula and is funding the study, invigilates the test and verbally encourages the FocusFlow group to "concentrate as hard as possible to show how well the formula works."
Identify and explain four methodological criticisms of this study regarding experimental control.
689 exam-style questions on AQA A Level Psychology Scientific processes. Each one has a worked solution and a mark scheme showing where the marks go.