In a study investigating the effect of binaural auditory stimulation on working memory, 40 university students were recruited. One group of 20 participants listened to 15 Hz beta-frequency binaural beats through headphones for 10 minutes before completing a complex backward digit-span task. The other group of 20 participants sat in silence for 10 minutes before completing the identical task. The performance was measured by the length of the longest sequence correctly recalled.
The researcher used an independent groups design, meaning different participants were assigned to each of the two conditions. The researcher is concerned that individual differences in baseline cognitive capacity or natural memory ability may have compromised the internal validity of the findings.
Explain one way in which the experiment could be changed to control for the problem of using different participants in each condition.
Practise AQA A Level Psychology Research methods with exam-style questions for A Level Psychology. 100 questions covering Experimental method, Observational techniques, Self-report techniques, Correlations, Content analysis (A-level only), Case studies (A-level only), Scientific processes, Data handling and analysis, and Inferential testing (A-level only), matched to the AQA A Level Psychology (7182) 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.