An experiment conducted with students and experienced clinicians demonstrated
very fast and on-line causal reasoning in the diagnosis of DSM-IV mental disorders.
The experiment also demonstrated that clinicians’ causal reasoning is triggered by
information that is directly related to the causal structure that explains the symptoms,
such as their temporal sequence. The use of causal theories was measured through
explicit, verbal diagnostic judgments and through the on-line registration of
participants’ reading times of clinical reports. To detect both on-line and off-line causal
reasoning, the consistency of clinical reports was manipulated. This manipulation was
made by varying the temporal order in which different symptoms developed in
hypothetical clients, and by providing explicit information about causal connections
between symptoms. The temporal order of symptoms affected the clinicians’ but not the
students’ reading times. However, off-line diagnostic judgments in both groups were
influenced by the consistency manipulation. Overall, our results suggest that clinicians
engage in fast and on-line causal reasoning processes when dealing with diagnostic
information concerning mental disorders, and that both clinicians and students engage in
causal reasoning in diagnostic judgment tasks.
