Harrison conducted an experiment to investigate the effect of weapon focus on the accuracy of eyewitness testimony. He showed a sample of 20 university students a video of a bank robbery where the perpetrator held either a large kitchen knife (weapon condition) or a leather wallet (control condition). Harrison then used a structured questionnaire with closed questions to measure their recall of the perpetrator's facial details.
Explain one improvement Harrison could make to his experiment.
120 exam-style questions on Edexcel A Level Psychology Content, covering Biological explanations of crime, Social explanations of crime, Cognitive and ethical interview techniques, Psychological formulation of offending, Cognitive-behavioural treatment for offenders, Biological treatment for offenders, Factors influencing eye-witness testimony, Factors influencing jury decision-making, Individual differences, and Developmental psychology. Each one has a worked solution and a mark scheme showing where the marks go.