Differentiating Categories and Dimensions: Evaluating the Robustness of Taxometric Analyses

Interest in modeling the structure of latent variables is gaining momentum, and many simulation studies suggest that taxometric analysis can validly assess the relative fit of categorical and dimensional models. The generation and parallel analysis of categorical and dimensional comparison data sets reduces the subjectivity required to interpret results by providing an objective Comparison Curve Fit Index (CCFI). This study takes advantage of developments in the generation of comparison data to examine the robustness of taxometric analyses to unfavorable data conditions. Very large comparison data sets are treated as populations from which many samples are drawn randomly, placing the method on a firmer statistical foundation and increasing its run-time efficiency. The impressive accuracy of the CCFI was consistent with prior findings and robust across novel manipulations of asymmetry, tail weight, and heterogeneous variances. Analyses, an empirical illustration using Minnesota Multiphasic Personality Inventory (MMPI) hypochondriasis data, and discussion focus on the practical implications for differentiating categories and dimensions.     

Dimensional Latent Structure of Callous-Unemotional Traits in German Adolescents: Results from Taxometric Analyses

Research on Child and Adolescent Psychopathology - A large amount of research has addressed the issue of the latent status of psychiatric disorders and related phenomena. We used a new taxometric...     

A Taxometric Analysis of Experiential Avoidance

Experiential avoidance, a trait-like construct referring to the tendency to rigidly avoid or change unpleasant internal experiences stemming from an unwillingness to experience them, is believed to contribute to the development and maintenance of various forms of psychopathology. Despite significant research on this construct, it remains unclear whether experiential avoidance is dimensional or categorical at the latent level. The current study examined the latent structure of experiential avoidance using three taxometric analytic approaches (MAXimum Eigenvalue, Mean Above Minus Below A Curve, Latent-Mode Factor Analysis) applied to data from two independent samples and using three widely used measures of experiential avoidance. The first sample (n = 922) completed the Multidimensional Experiential Avoidance Questionnaire (Gámez, Chmielewski, Kotov, Ruggero, & Watson, 2011), while the second sample (n = 615) completed the Brief Experiential Avoidance Questionnaire (Gámez et al., 2014) and Acceptance and Action Questionnaire-II (Bond et al., 2011). Across both samples and all three measures, experiential avoidance exhibited a dimensional structure. The clinical and research implications of this finding for experiential avoidance are discussed.     

Inferential reasoning in old age

Two experiments examined the effects of aging on the kind of inferential reasoning required in comprehending discourse. In Experiment 1 old subjects made more errors than young subjects in solving logical problems framed in everyday language. Unlike the young subjects they had more difficulty when the problems were spoken than when they were written. Experiment 2 revealed that old subjects are inefficient at extracting implicit information during reading; they fail to generate bridging inferences to supply missing information, so that comprehension is restricted to explicitly stated information. The results show that verbal reasoning ability is impaired in old age and that this affects language comprehension in both listening and reading although the deficit is more marked in listening.     

Taxometric analysis of the Levenson Self-Report Psychopathy scale

Levenson's Self-Report Psychopathy scale (Levenson, Kiehl, & Fitzpatrick, 1995) was administered to 1,972 male and female federal prison inmates, the results of which were subjected to taxometric analysis. We employed 4 taxometric procedures in this study: mean above minus below a cut (Meehl & Yonce, 1994), maximum slope (Grove & Meehl, 1993), maximum eigenvalue (Waller & Meehl, 1998), and latent-mode factor analysis (Waller & Meehl, 1998). The results showed consistent support for a dimensional interpretation of the latent structure of psychopathy, corroborating previous research conducted on the Psychopathy Checklist (e.g., Psychopathy Checklist-Revised; Hare, 2003) and Psychopathic Personality Inventory (Lilienfeld & Andrews, 1996) and denoting that psychopathy is a dimensional construct (degree of psychopathic characteristics) rather than a qualitatively distinct category of behavior (psychopath).     

Taxometric Analysis of the Levenson Self-Report Psychopathy Scale

Fifteen HIT cards were administered to 12 Ss before and after paired placebo and alcohol intravenous infusions in a Latin-square cross-over design. Separate sets of cards were used for placebo and alcohol infusions with cards from the A form administered before and the counterpart cards from the B form after each infusion. A significant increase in score in color was noted with the low level of intoxication as compared with placebo infusion. There were no significant differences between placebo and alcohol infusion on other HIT variables. Collateral data from previous alcohol intoxication experiments and other HIT studies suggest that the increase in color may be related to change in affect which accompanies the intoxication.     

Taxometric analyses of sexual orientation and gender identity

Taxa are nonarbitrary classes whose existence is an empirical question and not a matter of mere semantic convenience. Taxometric procedures detect whether numerical relations between purported indicators of conjectured taxa bear the hallmarks of true taxa. On the basis of theoretical considerations, the current study tested whether taxa underlie sexual orientation and related measures of gender identity. Two taxometric procedures, maximum covariance, making hits maximum (MAXCOV) and mean above minus below a cut (MAMBAC), were applied to Kinsey Scales and measures of childhood gender nonconformity and adult gender identity in a sample of nearly 5,000 members of the Australian Twin Registry. Results suggest that latent taxa underlie these measures. About 12-15% of men and 5-10% of women belong to latent taxa associated with homosexual preference. These percentages are greater than those of individuals who report homosexual preference, however, and hence it appears that an appreciable proportion of individuals in these taxa have heterosexual preference. An understanding of the origins of these latent taxa may be important to understanding the development of sexual orientation and gender identity.     

An Inferential Account of Model Explanation

Philosophia - This essay develops an inferential account of model explanation, based on Mauricio Suárez’s inferential conception of scientific representation and Alisa Bokulich’s...     

An Inferential Model of Scientific Understanding

In this article I argue that two current accounts of scientific understanding are incorrect and I propose an alternative theory. My new account draws on recent research in cognitive psychology which reveals the importance of making causal and logical inferences on the basis of incoming information. To understand a phenomenon we need to make particular kinds of inferences concerning the explanations we are given. Specifically, we come to understand a phenomenon scientifically by developing mental models that incorporate the correct causal and logical properties responsible for the causes or logical properties of the phenomenon being explained.     

The Latent Structure of Psychopathy in Youth: A Taxometric Investigation

Using taxometric procedures, the latent structure of psychopathy was investigated in two studies of children and adolescents. Prior studies have identified a taxon (i.e., a natural category) associated with antisocial behavior in adults as well as children and adolescents. However, features of this taxon suggest that it is not psychopathy but rather a broader class consistent with the construct of life course persistent antisocial behavior. Because the only prior study of youth used a non-clinical sample, the base rate of psychopathy may have been too low to reveal a psychopathy taxon, especially against the background of a broader and more prevalent antisocial behavior taxon. Therefore, this investigation sought to increase the likelihood of finding a psychopathy taxon (should one exist) by increasing its expected base rate through inclusion of clinical cases in the samples studied. Results produced evidence for both a broad antisocial behavior problem taxon consistent with past research and a much lower base rate taxon consistent with prevalence expectations for psychopathy. These findings support the existence of latent taxa for both psychopathy and a broader class of antisocial behavior problems. Further taxometric research appears to be warranted, which should use a broader array of indicators, with greater specificity to psychopathy.     

Inferential errors in taxometric analyses of ordered three-class constructs

Taxometric analysis (Waller & Meehl, 1998) has become a popular tool for investigating whether personality and psychopathology constructs are better modeled as dimensional or categorical. Monte Carlo evidence for the validity of taxometric methods, however, has been restricted to data that are derived either from latent dimensional or dichotomous models. There are various circumstances in which the correct model for a psychosocial construct could involve three or more ordered classes. It was demonstrated both mathematically and empirically that under these circumstances, the results of taxometric analyses can lead to incorrect conclusions about the population structure. Recommendations are provided for future studies intended to distinguish between categorical and dimensional structures.     

Inferential confusion and obsessive beliefs in obsessive-compulsive disorder

The goal of the present study was to investigate whether inferential confusion could account for the relationships between obsessional beliefs and obsessive-compulsive disorder (OCD). The Inferential Confusion Questionnaire and the Obsessive Beliefs Questionnaire were administered to a sample of 85 participants diagnosed with OCD. Results showed that the relationship between obsessive beliefs and obsessive-compulsive symptoms decreased considerably when controlling for inferential confusion. Conversely, the relationship between inferential confusion and obsessive-compulsive symptoms was not substantially affected when controlling for obsessive beliefs. Since inferential confusion has an overlap with overestimation of threat, a competing hypothesis for the results was investigated. Results indicated that inferential confusion was factorially distinct from overestimation of threat, and that the independent construct of inferential confusion remains significantly related to obsessive-compulsive symptoms when controlling for anxious mood. These results are consistent with the claim that inferential confusion may be a more critical factor in accounting for OCD symptoms than are obsessive beliefs and appraisals.     

Taxometric analysis of fuzzy categories: a Monte Carlo study

A small Monte Carlo study examined the performance of a form of taxometric analysis (the MAXCOV procedure) with fuzzy data sets. These combine taxonic (categorical) and nontaxonic (continuous) features, containing a subset of casts with intermediate degrees of category membership. Fuzzy data sets tended to yield taxonic findings on plot inspection and two popular consistency tests, even when the degree of fuzziness, i.e., the proportion of intermediate cases, was large. These results suggest that fuzzy categories represent a source of pseudotaxonic inferences, if on is understood in the usual binary, "either-or" fashion. This in turn implies that dichotomous causes cannot be confidently inferred when taxometric analyses yield apparently taxonic findings.     

On the Argumentative Strength of Indirect Inferential Conditionals

Inferential or epistemic conditional sentences represent a blueprint of someone’s reasoning process from premise to conclusion. Declerck and Reed (2001) make a distinction between a direct and an indirect type. In the latter type the direction of reasoning goes backwards, from the blatant falsehood of the consequent to the falsehood of the antecedent. We first present a modal reinterpretation in terms of Argumentation Schemes of indirect inferential conditionals (IIC’s) in Declerck and Reed (2001). We furthermore argue for a distinction between epistemic-modal strong and deontic-modal weak IIC’s. In addition, we extend the category of the indirect inferential conditionals in order to include several other deontic-modal subtypes. On the basis of the undesirability of the consequent the hearer in these cases infers that the antecedent is also undesirable. In this way the rhetoric-argumentative strategy of Reductio ad Absurdum is extended from the realm of deductive reasoning to that of practical reasoning.