Carlsson et al. (2000) relied on secondary data, including animal studies, to formulate their glutamatergic hypothesis of schizophrenia.
Suggest one modification to the design of this study that would address a limitation of using secondary data, and explain how this modification would improve the validity of their conclusions.
Practise Edexcel A Level Psychology Studies with exam-style questions for A Level Psychology. 119 questions covering Classic study: van IJzendoorn and Kroonenberg (1988), Contemporary study: Cassibba et al. (2013), Contemporary study: Gagnon-Oosterwaal et al. (2012), and Contemporary study: Li et al. (2013), matched to the Edexcel A Level Psychology (9PS0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
