Scott W. Allen

Role of Specific Similarity in a Medical Diagnostic Task

Three experiments are reported showing that diagnosis of skin disorders by medical residents and general practitioners was facilitated by similar cases previously seen in the same context. Diagnosis of similar cases was facilitated more than that of dissimilar cases in the same diagnostic category, demonstrating that facilitation was not solely due to activation of the diagnostic category as a whole. Because diagnosis was posed in a multiple-choice format that always included the correct diagnosis, the relative disadvantage of dissimilar items was not due to the unavailability of the category name. The similarity effect also occurred with 2-week delay between the initial case and the test cases. Variations in diagnostic procedure, ranging from giving a quick first impression to arguing for given alternative diagnoses before selection, did not interact with the effect of similarity. This result suggests that the similarity effect is not strongly dependent on a particular diagnostic strategy.

Experimental studies of learning dermatologic diagnosis: The impact of examples

Two experiments investigate the role of examples in learning dermatologic diagnosis. Medical students were given a written set of normative rules for the diagnosis of six common skin disorders, followed by practice applying those rules to a set of photographic images. On subsequent testing, the accuracy of diagnosing a set of critical new items depended strongly on the diagnosis of the most similar practice item, even when the test item was typical of its disorder. This suggests that the effect of the practice items was not restricted to providing practice in applying the rules. The influence of similar practice items persisted after a week between practice and test. The implication is that exposure to many examples may be a critical component of clinical reasoning.

A visual familiarity account of evidence for orthographic processing in pigeons (Columbia livia) : a reply to Scarf, Corballis, Güntürkün, and Colombo (2017)

AbstractScarf et al. (Proc Natl Acad Sci 113(40):11272–11276, 2016) demonstrated that pigeons, as with baboons (Grainger et al. in Science 336(6078):245–248, 2012; Ziegler in Psychol Sci. https://doi.org/10.1177/0956797612474322, 2013), can be trained to display several behavioural hallmarks of human orthographic processing. But, Vokey and Jamieson (Psychol Sci 25(4):991–996, 2014) demonstrated that a standard, autoassociative neural network model of memory applied to pixel maps of the words and nonwords reproduces all of those results. In a subsequent report, Scarf et al. (Anim Cognit 20(5):999–1002, 2017) demonstrated that pigeons can reproduce one more marker of human orthographic processing: the ability to discriminate visually presented four-letter words from their mirror-reversed counterparts (e.g. “LEFT” vs. “ ”). The current report shows that the model of Vokey and Jamieson (2014) reproduces the results of Scarf et al. (2017) and reinforces the original argument: the recent results thought to support a conclusion of orthographic processing in pigeons and baboons are consistent with but do not force that conclusion.