In the revised 'Reading the Mind in the Eyes' test study by Baron-Cohen et al., the high-functioning autistic/Asperger's syndrome group (Group 1) was matched on intelligence quotient (IQ) with a control group of typical adults (Group 4).
Explain how failing to match these groups on IQ could have compromised the internal validity of the study.
47 exam-style questions on OCR A Level Psychology Understanding disorders, covering Freud (1909): Little Hans and Baron-Cohen et al. (1997): Autism in adults. Each one has a worked solution and a mark scheme showing where the marks go.