Unicorns, snarks, and personality types: A review of the first 102 taxometric studies of personality

Abstract

Objective: The default assumption among most psychologists is that personality varies along a set of underlying dimensions, but belief in the existence of discrete personality types persists in some quarters. Taxometric methods were developed to adjudicate between these alternative dimensional and typological models of the latent structure of individual differences. The aim of the present review was to assess the taxometric evidence for the existence of personality types. Method: A comprehensive review yielded 102 articles reporting 194 taxometric findings for a wide assortment of personality attributes. Results: Structural conclusions differed strikingly as a function of methodology. Primarily older studies that did not assess the fit of observed data to simulated dimensional and typological comparison data drew typological conclusions in 65.2% (60/92) of findings. Primarily newer studies employing simulated comparison data supported the typological model in only 3.9% (4/102) of findings, and these findings were largely in the domain of sexual orientation rather than personality in the traditional sense. Conclusions: In view of strong Monte Carlo evidence for the validity of the simulated comparison data method, it is highly likely that personality types are exceedingly scarce or non-existent, and that many early taxometric research findings claiming evidence for such types are spurious.

Dimensions over categories: a meta-analysis of taxometric research

“…Since the advent of data simulation-based procedures, taxonic findings have become scarce. It has grown increasingly clear that taxa are rare in the field of psychopathology and perhaps mythical in the field of personality (Haslam, 2019). This meta-analysis supports the findings of previous, non-meta-analytic reviews of the taxometric literature by establishing that taxonic findings are infrequent when appropriate methodological controls are applied, and by quantifying the powerful bias toward taxonic inferences that exists when they are not.…”

Answering Questions About the Hierarchical Taxonomy of Psychopathology (HiTOP): Analogies to Whales and Sharks Miss the Boat

“…The science of taxometrics was developed specifically to test quantitatively whether variables are better characterized as categories or continua. As taxometric methods have improved, no common form of psychopathology has yet shown evidence of being categorical rather than continuous (Haslam, 2019;Haslam et al, 2020). The decision is therefore based on empirical evidence.…”

“…Rather, it is a statistical method for testing hypotheses about the existence of categorical entities ("taxa"). Further, taxometrics has provided strong evidence to favor a taxonomy of continuous dimensions (such as HiTOP) in which features of psychopathology are classified, rather than a taxonomy of discrete categories (such as DSM) in which people are classified (Haslam, 2019;Haslam et al, 2020). Indeed, the taxometrics literature is the main reason that HiTOP does not contain any categorical taxa at present, and this contribution of taxometrics to HiTOP has been described in consortium publications (e.g., .…”

Psychomotor Predictive Processing

“…Even with a critical realist framing, there are challenges for the application of modeling methods used in previous PGNW studies during the planning and operation of human–robot systems. For example, methodologies for defining personality type, hardiness levels, fascia densification, and body memory can contribute to approximate descriptions with indeterminate boundaries, such as those between one personality type category and another [ 145 ]. Moreover, fascia research is at an early stage [ 146 ].…”