A sports science researcher conducted a study to investigate the effect of hydration status on spatial memory performance.
Ten endurance runners participated in a 6-day trial. Every morning, they completed a 10 km run on a treadmill in a temperature-controlled laboratory.
On three of the days, the researcher instructed the runners to drink a fixed high volume of water (2 litres) in the two hours leading up to the run. On the other three days, they were instructed to drink a low volume of water (0.25 litres). The order of these hydration conditions was randomized for each runner.
One hour after completing each run, the runners completed a standardized computer-based spatial memory test, scored from 0 to 100. Apart from the controlled hydration sessions, participants were told to go about their usual daily schedules.
Suggest one extraneous variable that could have affected the results of this study. Explain why it would have been important to control this extraneous variable and how it could have been controlled in this study.
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.