Speed kills? Speed, accuracy, encapsulations and causal understanding.

BACKGROUND: The role of basic science, which provides causal explanations for clinical phenomena in medical education, is poorly understood. Schmidt has postulated that expert clinicians maintain this knowledge in 'encapsulated' form, indexed by words or phrases describing the processes. In the present paper we show that students who learn causal explanations have a more coherent understanding of the relation between diseases and clinical features which, in turn, influences recognition of words or phrases describing 'encapsulated knowledge' and the ability to maintain performance under speeded conditions. HYPOTHESES: In comparison to students who simply learn the features of 4 diagnostic categories, students who learn a causal explanation will: (a) recognise words describing encapsulated knowledge more accurately and (b) maintain or improve diagnostic performance under speeded conditions. METHODS: Two studies were conducted involving 4 'pseudo-endocrinology' diseases and undergraduate psychology students. One group learned signs and symptoms alone; the second group also learned a causal explanation. In study 1, they were then given a recognition memory task. In study 2, they were asked to diagnose new cases either (i) as quickly as possible or (ii) taking their time. RESULTS: In study 1, while there was no difference in recognising old words (90% versus 91%), the causal group was better able to recognise encapsulated and novel consistent words (50% versus 41%) (P = 0.02). In study 2 there was an interaction; causal students performed better under speeded conditions (71% versus 66%) but worse under thoroughness conditions (67% versus 73%), as predicted. CONCLUSIONS: Causal understanding leads to more coherent understanding of clinical conditions, which in turn leads to expert-like behaviour.

The value of basic science in clinical diagnosis.

BACKGROUND: The role of basic science knowledge in clinical diagnosis is unclear. There has been no experimental demonstration of its value in helping students recall and organize clinical information. This study examines how causal knowledge may lead to better recall and diagnostic skill over time. METHOD: Undergraduate medical students learned either four neurological or rheumatic disorders. One group learned a basic science explanation for the symptoms. The other learned epidemiological information. Both were then tested with the same set of clinical cases immediately after learning and one week later. RESULTS: On immediate test, there was no difference in accuracy (70% for both groups). However, one week later, performance in the epidemiology group dropped to 51%; the basic science group only dropped to 62%. CONCLUSIONS: Basic science knowledge relating causal knowledge to disease symptoms can improve diagnostic accuracy after a delay.