Conceptual and empirical analysis of some assumptions of an explicitly typological theory.

Abstract

The criteria for typology described by Mendelsohn, Weiss, and Feimer (1982) are reexamined. It is argued that the first of the two criteria for single-variable typologies, multimodality, is a weak one for psychological data and that only the second criterion, discontinuity against an external variable, is telling. It is agreed that these authors' requirement that multiple-variable typologies combine interactively to predict external variables is a mandatory one, although it is not one that is diagnostic of typology. These issues are illustrated by a multiple-variable, explicitly system specified by the Myers-Briggs Type Indicator (MBTI). This system predicts both single-variable and interactive relationships against external criteria and explicitly proposes discontinuity at the scales' midpoints. The present MBTI study, like others, yielded no predictor bimodality, though the distribution displayed platykurtosis, the index of which is maximized with bimodal distributions. Similarly, the criterion distribution did not display bimodality, though conventional assessments of differences in distribution location evidenced sharp discontinuities at the midpoint for one variable, Sensing-Intuition, against two criteria, and for a second variable, Extraversion-Introversion, against one criterion. Predictor variable interactions were only weakly displayed. A review of relevant MBTI research, coupled with these findings, challenges pessimism about the verifiability of all systems, suggesting that further investigation of this approach, using appropriate data analytic procedures, would be fruitful. A cogent discussion of the conceptual issues associated with use of typologies was recently provided by Mendelsohn, Weiss, and Feimer (1982), who reexamined what were described as the implicitly typological assumptions underlying the interpretation of a well-known data set (Block, von der Lippe, & Block, 1973). The Mendelsohn et al. critique produced a heated response by the Block group (Block & Ozer, 1982) and a retort by the Mendelsohn faction (Weiss, Mendelsohn, & Feimer, 1982). This debate, though marked by passion and occasional hyperbole, actually begins to provide a useful airing of the scientific and psychometric criteria for explicit and implicit typologies, as well as for the nontypological labels that psychologists are notoriously fond of emitting.