Inducing System-1-type diagnostic reasoning in second-year medical students within 15 minutes.

Diagnostic reasoning literature debates the significance of "dual-process theory" and the importance of its constituent types of thinking: System-1and System-2. This experimental study aimed to determine whether novice medical students could be trained to utilize System-1 thinking when making diagnoses based on chest X-rays. Second-year medical students were recruited and presented with a series of eight online chest X-rays cases. Participants were shown half of the cases repeatedly during a training phase and the other half only twice. During the final test phase, they were shown all eight cases, providing a diagnosis as a free text answer. Dependent variables were diagnostic accuracy and response time. Thirty-two students participated. During the test phase, students responses were significantly more accurate and faster for cases which had been seen repeatedly during the training phase (mean score = 3.56/4, mean time = 2.34 s) compared with cases which had been seen only twice (mean score = 1.59/4, mean time = 7.50 s). This study demonstrates that it is possible to induce in novice students the speed-to-diagnosis and diagnostic accuracy typical of System-1-type reasoning. The full experimental design and the chest X-rays used may provide new opportunities to explore some of the issues surrounding dual-process theory.