Dual process models of clinical reasoning: the central role of knowledge in diagnostic expertise.

Diagnostic reasoning is frequently discussed in terms of System 1 (thinking fast) and System 2 (thinking slow). The authors of this review present evidence against the claim that diagnostic error stems solely from System 1 thinking. They conclude that errors originate from both System 1 and System 2 thinking. Errors typically occur due to lack of access to the appropriate knowledge, and neither system is essential to the process of diagnostic reasoning.