Dr. Aris conducted a laboratory experiment to investigate whether ambient background noise affects the efficiency of working memory. A sample of participants was asked to perform a complex working memory task (the dual n-back task) while exposed to high-intensity white noise (80 dB80\text{ dB}80 dB). The following day, the same participants completed an equivalent dual n-back task in a completely silent environment (0 dB0\text{ dB}0 dB).
Identify the independent variable (IV) in this investigation.
186 exam-style questions on Edexcel A Level Psychology Research methods and skills, covering Research methods and skills. Each one has a worked solution and a mark scheme showing where the marks go.