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Biomedical subjects

P E Meehl

Publications and source records attributed to P E Meehl.

17 recordsLinked to original sources

Primary and secondary hypohedonia.

Having shown taxometrically that there exists a hypohedonic schizotypal taxon in a college population, J. J. Blanchard, S. W. Gangestad, S. A. Brown, and W. P. Horan (2000) suggested that P. E. Meehl erred in revising his 1962 theory by postulating a normal-range individual differences variable of hedonic capacity that potentiates schizotypy into schizophrenia. The aversive drift and secondary anhedonia of Meehl's theory imply that the schizotypal taxon will generate hypohedonic taxonicity in an adult population. Psychometrically measurable hedonic disposition (as distinguished from genetic primary hedonic capacity) is "dragged along" by the schizogene, especially in the social domain. To choose between causal interpretations, it could be ascertained whether the schizotypal anhedonic taxon is composed of individuals who are schizotaxic on the basis of psychophysiological, cognitive, and soft neurologic indicators.

Affect↗

Bootstraps taxometrics. Solving the classification problem in psychopathology.

Classification in psychopathology is a problem in applied mathematics; it answers the empirical question "Is the latent structure of these phenotypic indicator correlations taxonic (categories) or nontaxonic (dimensions, factors)?" It is not a matter of convention or preference. Two taxometric procedures, MAMBAC and MAXCOV-HITMAX, provide independent tests of the taxonic conjecture and satisfactorily accurate estimates of the taxon base rate, the latent means, and the valid and false-positive rates achievable by various cuts. The method requires no gold standard criterion, applying crude fallible diagnostic "criteria" only in the phase of discovery to identify plausible candidate indicators. Confidence in the inference to taxonic structure and numerical accuracy of latent values is provided by multiple consistency tests, hence the term coherent cut kinetics for the general approach. Further revision of diagnostic systems should be based on taxometric analysis rather than on committee decisions based on clinical impressions and nontaxometric research.

Humans↗

Simple regression-based procedures for taxometric investigations.

Certain theories of psychopathology postulate the existence of distinct latent populations of individuals. By analogy with biology, we call such latent populations "taxa" and we call the statistical testing of such theories "taxometrics." Taxometric procedures are robust; they do not make restrictive distributional assumptions. However, they have two disadvantages for nonstatistician users: (1) they are developed via algebra hard for many nonstatistician users intuitively to accept; and (2) computational software is not widely available. We address these problems by presenting a simple taxometric procedure, MAXSLOPE, based on regression plots for pairs of variables. This procedure is easily implemented using commonly available software and is intuitively rather easy to understand. We apply it to two artificial datasets. One dataset, used to explain the graphs, shows clear-cut evidence of taxa. The other example shows less clear grouping structure and is used to show that the proposed graphical procedure works even in nonideal cases. Comparisons are made with currently used procedures of cluster analysis and multivariate normal mixture analysis.

Cluster Analysis↗

Needs (Murray, 1938) and state-variables (Skinner, 1938).

Skinner's concept of drive as a state-variable and his powerful rationale for introducing it agree closely with Murray's treatment of need. Operant behaviorists' usual deprecation of motivation in favor of stimulus control arises partly from features of parameters, insufficiently explored in some regions, of Skinner box research. For human adults on rich reinforcement schedules, response selection is chiefly controlled by the regnant motive. Skinner's life-long interest in inner events and translating psychodynamic concepts into behaviorese was obscured by his metalanguage philosophy of science (behaviorism).

Animals↗

Clinical versus actuarial judgment.

Professionals are frequently consulted to diagnose and predict human behavior; optimal treatment and planning often hinge on the consultant's judgmental accuracy. The consultant may rely on one of two contrasting approaches to decision-making--the clinical and actuarial methods. Research comparing these two approaches shows the actuarial method to be superior. Factors underlying the greater accuracy of actuarial methods, sources of resistance to the scientific findings, and the benefits of increased reliance on actuarial approaches are discussed.

Actuarial Analysis↗

Schizotaxia revisited.

A conjectured neural integrative defect (schizotaxia), due to a dominant schizogene completely penetrant for a parametric aberration in synaptic signal selectivity (hypokrisia), gives rise under ordinary social learning regimens to schizotypy, a personality showing ambivalence, aversive drift, dereism, autism, and cognitive slippage. Given unfavorable polygenic potentiators (eg, introversion, hypohedonia, and anxiety) and adverse life experiences (eg, childhood trauma or adult misfortune), around 10% develop schizophrenia. That schizophrenia is basically a neurologic disorder does not contradict whatever is known about its psychodynamics, nor preclude efficacy for psychotherapy or other psychosocial interventions. Research should concentrate on soft neurology and psychophysiology as indicators, being closer in the causal chain to the schizogene than psychometric, social, or high-level cognitive processes. Taxometric statistics are appropriate to testing a major locus model not simplistically formulated.

Central Nervous System↗

Causes and effects of my disturbing little book.

Review and reflection indicate that no more than 5% of what was written in the 1954 book entitled, Clinical Versus Statistical Prediction (Meehl, 1984), needs to be retracted 30 years later. If anything, these retractions would result in the book's being more actuarial than it was. Seven factors appear to account for the failure of mental health professionals to apply in practice the strong and clearly supported empirical generalizations demonstrating the superiority of actuarial over clinical prediction.

Clinical Competence↗

A funny thing happened to us on the way to the latent entities.

Inferred latent entities, whether those of psychoanalysis, factor analysis, or cluster analysis, have declined in value for many clinical psychologists, both as tools of practice and as objects of theoretical interest. Behavior modification, rational-emotive therapy, crisis intervention, psycho-pharmacology, and actuarial prediction all tend to minimize reliance on latent entities in favor of purely dispositional concepts. Behavior genetics is, however, a powerful movement to the contrary. As regards categorical entities (types, taxa, syndromes, diseases), history reveals no impressive examples of their discovery by cluster algorithms; whereas organic medicine and psychopathology have both discovered many taxonic entities without reliance on formal (statistical) cluster methods. I offer eight reasons for this strange condition, with associated suggestions for ameliorating it. Adopting a realist instead of a fictionist approach to taxonomy, I give high priority to theory-based mathematical derivation of quantitative consistency tests for all taxometric results. I urge a large scale cooperative survey of taxometric methods based on Monte Carlo runs, biological pseudoproblems where the true axon is independently known, and live problem in genetics, organic medicine, and psychopathology. An empirical example of taxometric bootstrapping and consistency testing was presented from my own current research on schizotypy.

Humans↗

Testing a single dominant gene theory without an accepted criterion variable.

In testing a single dominant gene hypothesis we often are not able directly to measure the inherited trait. A typical situation is one where we only have one or more fallible indicators of the trait under study. The statistical method proposed requires that we have measurements on several such indicators for each of the parents of probands known to possess the trait.

Genes, Dominant↗