The taxonicity of schizotypy: a replication

P.E. Meehl's model (1962, 1990) of schizotypy and the development of schizophrenia implies that the structure of liability for schizophrenia is dichotomous, hypothesizing that a "schizogene" determines one's membership in a latent class (or taxon; P.E. Meehl & R. R. Golden, 1982). The present study sought to replicate earlier findings concerning the taxonic latent structure and general population base rate of schizotypy (M. F. Lenzenweger & L. Korfine, 1992). P.E. Meehl's (1973; P.E. Meehl & R. R. Golden, 1982) MAXCOV-HITMAX taxometric analytic procedures were applied to a subset of items from the Perceptual Aberration Scale (PAS; L. J. Chapman, J. P. Chapman, & M. L. Raulin, 1978), a prominent psychometric index of schizotypy, derived from a new randomly ascertained nonclinical university sample (N = 1,646). Consistent with the authors' previous results as well as Meehl's conjectures, the data strongly suggest that schizotypy, as assessed by the PAS, is taxonic at the latent level with a low general population taxon base rate (i.e., < .10). Moreover, individuals falling within the putative schizo-taxon underlying the PAS present greater levels of schizotypic phenomenology than nontaxon members. The taxometric analysis of the psychological trait of femininity also reveals that the MAXCOV-HITMAX procedure can detect a latent dimension, when one is hypothesized to exist, and the procedure does not appear to generate "spurious" evidence for taxonicity as a function of the psychometric format (e.g., true-false) of the data under analysis. The statistical implication of a taxonic entity occurring at a low base is discussed with respect to results obtained using the MAXCOV-HITMAX technique.