Fast and frugal models of clinical judgement in novice and expert physicians

Our objective was to study whether “compensatory” models provide better descriptions of clinical judgment than fast and frugal models, according to expertise and experience. Fifty practitioners appraised 60 vignettes describing a child with an exacerbation of asthma and rated their propensities to admit the child. Linear logistic (LL) models of their judgments were compared with a matching heuristic (MH) model that searched available cues in order of importance for a critical value indicating an admission decision. There was a small difference between the 2 models in the proportion of patients allocated correctly (admit or not-admit decisions), 91.2% and 87.8%, respectively. The proportion allocated correctly by the LL model was lower for consultants than juniors, whereas the MH model performed equally well for both. In this vignette study, neither model provided any better description of judgments made by consultants or by pediatricians compared to other grades and specialties.

Belief, Knowledge and Expertise. The emergence of the lay expert in medical sociology

The paper has three main aims. First, to trace – through the pages of the Journal – the changing ways in which lay understandings of health and illness have been represented during the 1979-2002 period. Second, to say something about the limits of lay knowledge (and particularly lay expertise) in matters of health and medicine. Third, to call for a re-assessment of what lay people can offer to a democratised and customer sensitive system of health care and to attempt to draw a boundary around the domain of expertise. In following through on those aims, the author calls upon data derived from three current projects. These latter concern the diagnosis of Alzheimer’s disease in people with Down’s syndrome; the development of an outcome measure for people who have suffered a traumatic brain injury; and a study of why older people might reject annual influenza vaccinations. Key words: Lay health beliefs, lay expertise, Alzheimer’s, Traumatic Brain Injury, Vaccinations

Optic variables used to judge future ball arrival position in expert and novice soccer players

Although many studies have looked at the perceptual-cognitive strategies used to make anticipatory judgments in sport, few have examined the informational invariants that our visual system may be attuned to. Using immersive interactive virtual reality to simulate the aerodynamics of the trajectory of a ball with and without sidespin, the present study examined the ability of expert and novice soccer players to make judgments about the ball's future arrival position. An analysis of their judgment responses showed how participants were strongly influenced by the ball's trajectory. The changes in trajectory caused by sidespin led to erroneous predictions about the ball's future arrival position. An analysis of potential informational variables that could explain these results points to the use of a first-order compound variable combining optical expansion and optical displacement.

The Rise and Fall of the Legal Expert System

Those very few of us who were critical of the rise of legal expert systems in the early 1980s probably wonder, in idle moments, whether there is a possibility of rejuvenation of an approach which was once multi¬various and is now obscure and esoteric. Is it possible that after rising and falling, that legal expert system research programme could rise again? What were the conditions which gave impetus to the field and could they be repeated? In this article I want to return, with a personal viewpoint, on the rise of expert systems and why – despite their failure – the appeal of commoditising legal expertise continues to allure the unwary.

Gaze fixation improves the stability of expert juggling

Novice and expert jugglers employ different visuomotor strategies: whereas novices look at the balls around their zeniths, experts tend to fixate their gaze at a central location within the pattern (so-called gaze-through). A gaze-through strategy may reflect visuomotor parsimony, i.e., the use of simpler visuomotor (oculomotor and/or attentional) strategies as afforded by superior tossing accuracy and error corrections. In addition, the more stable gaze during a gaze-through strategy may result in more accurate movement planning by providing a stable base for gaze-centered neural coding of ball motion and movement plans or for shifts in attention. To determine whether a stable gaze might indeed have such beneficial effects on juggling, we examined juggling variability during 3-ball cascade juggling with and without constrained gaze fixation (at various depths) in expert performers (n = 5). Novice jugglers were included (n = 5) for comparison, even though our predictions pertained specifically to expert juggling. We indeed observed that experts, but not novices, juggled significantly less variable when fixating, compared to unconstrained viewing. Thus, while visuomotor parsimony might still contribute to the emergence of a gaze-through strategy, this study highlights an additional role for improved movement planning. This role may be engendered by gaze-centered coding and/or attentional control mechanisms in the brain.