Joseph A. Horvath

A Prototype View of Expert Teaching

We call for a reconceptualization of teaching expertise, one grounded in a psychological understanding of how (a) experts differ from nonexperts, and (b) people think about expertise as they encounter it in real-world settings. To this end, we propose that teaching expertise be viewed as a category that is structured by the similarity of expert teachers to one another rather than by a set of necessary and sufficient features. A convenient way of thinking about such categories is in terms of a central exemplar or prototype (Rosch, 1978), and we believe that a prototype view can contribute in important ways to a dialogue on expert teaching. Most importantly, a prototype view provides a way of thinking about expertise that incorporates standards (such that not every experienced practitioner is an expert) but also allows for variability in the profiles of individual experts. In this article, we outline a rudimentary model of prototype-based categorization and identify possible features, drawn from psychological research, on which the family resemblance among expert teachers may be founded. We discuss several implications of the prototype view for understanding and fostering expertise among teachers.

Identifying and Assessing Tacit Knowledge: Understanding the Practical Intelligence of Military Leaders

Abstract Tacit knowledge (TK) is knowledge drawn from everyday experience that helps individuals to solve real-world, practical problems. This study applied a method for identifying and assessing TK to the domain of military leadership in order to understand why some leaders are more successful than others. Interviews were conducted with Army officers at three levels of leadership in order to identify the type of practical, experience-based knowledge that is not necessarily part of formal training or doctrine. Subsequently, the Tacit Knowledge for Military Leaders (TKML) inventory, consisting of a series of leadership scenarios, was developed to assess the amount of knowledge leaders possess. Three versions of the TKML were administered to a total of 562 leaders at the platoon, company, and battalion levels. At all three levels, TKML scores correlated with ratings of leadership effectiveness from either peers or superiors, and the scores explained variance in leadership effectiveness beyond a test of general verbal ability and a test of TK for managers. These results indicate that domain-specific TK can explain individual differences in leadership effectiveness and suggest that leadership development initiatives should include efforts to facilitate the acquisition of TK.

Rabies virus binding to the nicotinic acetylcholine receptor alpha subunit demonstrated by virus overlay protein binding assay.

A virus overlay protein binding assay was used to study binding of 125I-labelled rabies virus to the acetylcholine receptor (AChR) from Torpedo californica electric organ membranes. After gel electrophoresis of electric organ membranes and transfer of proteins to nitrocellulose, 125I-labelled alpha-bungarotoxin, a curaremimetic neurotoxin, bound to a 40 kDa band and 125I-labelled rabies virus bound to 51 kDa and 40 kDa bands. Binding of rabies virus to the 40 kDa band was inhibited by unlabelled alpha-bungarotoxin. In blots of affinity-purified AChR, labelled virus bound to the 40 kDa alpha subunit and was competed by alpha-bungarotoxin. Based on binding of rabies virus to the alpha subunit and the ability of alpha-bungarotoxin to compete for binding, rabies virus appears to bind to the neurotoxin-binding site of the nicotinic AChR alpha subunit.