In a laboratory experiment investigating the effects of screen blue-light filters on cognitive performance, researchers recruited 15 young children (aged 6 to 8) from a single primary school to complete a 5-minute spatial rotation puzzle on a tablet, under either a standard high-intensity screen setting or a blue-light filtered 'warm' screen setting. Performance was measured by the total time taken (in seconds) to complete the puzzle.
Explain two improvements that the researchers could make to this study.
638 exam-style questions on Edexcel A Level Psychology Methods. Each one has a worked solution and a mark scheme showing where the marks go.