In a laboratory experiment investigating the effectiveness of a new type of blue-light filtering lens on reducing eye strain during prolonged screen work, researchers compared an experimental group wearing the blue-light filtering glasses with a control group wearing identical-looking glasses with standard clear lenses.
The researchers were concerned that the outcome measures—including self-reported visual fatigue and scores on an attention-tracking computer task—might be biased by both demand characteristics and investigator effects.
Explain how the researchers could design or conduct this study to eliminate or reduce both demand characteristics and investigator effects.
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.