The psychology of diagnostic error



Diagnostic errors in medicine occur frequently and the consequences for the patient can be severe. Cognitive errors as well as system related errors contribute to the occurrence of diagnostic error, but it is generally accepted that cognitive errors are the main contributor. The diagnostic reasoning process in medicine, is an understudied area of research. One reason is because of the complexity of the diagnostic process and therefore the difficulty to measure diagnostic errors and the causes of diagnostic error. In this paper, I discuss some of the complexities of the diagnostic process. I describe the dual-process theory, which defines two reasoning modes, 1. a fast, automatic and unconscious reasoning mode called system 1, and a slow and analytic reasoning mode called system 2. Furthermore, the main cognitive causes of diagnostic error are described.

General Information

Keywords: diagnostic error, patient safety, cognitive biases, clinical reasoning, psychology

Journal rubric: Psychodiagnostics

Article type: scientific article


For citation: Zwaan L. The psychology of diagnostic error. Eksperimental'naâ psihologiâ = Experimental Psychology (Russia), 2015. Vol. 8, no. 3, pp. 91–98. DOI: 10.17759/exppsy.2015080309. (In Russ., аbstr. in Engl.)


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Information About the Authors

Laura Zwaan, Research scientist, Erasmus University Medical Center, Institute for Medical Education Research, Rotterdam, Netherlands, e-mail:



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