This review describes how measures of a prominent threedimensional hierarchical model of personality traits relate to substance use. H. J. Eysenck proposed a biologically based model of personality that gave rise to related models such as those of J. A. Gray, C. R. Cloninger, and M. Zuckerman. The varying role of impulsivity-a trait related to disinhibition, approach motivation, novelty seeking, and sensation seeking-in successive self-report measures of this model, including the Eysenck Personality Inventory (EPI) and Eysenck Personality Questionnaire (EPQ),

The importance of the interpersonal circle in organizing the interpersonal domain is complemented by its empirical relations with broader personality taxonomies and with more specific personality variables. Yet circumplex structure in interpersonal measures has often been investigated using the "eyeball test" rather than using circumplex criteria of known effectiveness. Simulations (Acton, 1999) showed the effectiveness of 5 exploratory criteria (3 entirely new) that assess the properties of equal spacing, constant radius, and no preferred rotation. Along with Browne's (1992) criterion, these were applied to the Interpersonal

An important, sometimes controversial feature of all psychological phenomena is whether they are categorical or dimensional. A conceptual and psychometric framework is described for distinguishing whether the latent structure behind manifest categories (e.g., psychiatric diagnoses, attitude groups, or stages of development) is category-like or dimension-like. Being dimension-like requires (a) withincategory heterogeneity and (b) between-category quantitative differences. Being category-like requires (a) within-category homogeneity and (b) between-category qualitative differences. The relation between this classification and abrupt versus smooth differences is discussed. Hybrid structures are possible. Being category-like is itself a matter of degree; the authors offer a formalized framework to determine this degree. Empirical applications to personality disorders, attitudes toward capital punishment, and stages of cognitive development illustrate the approach.

The hypothesis, originally proposed by Galton and elaborated by Spearman, that there is a functional correspondence between sensory discrimination and general intelligence ( g) continues to spark debate. Previous findings suggest that pitch discrimination and tactile discrimination are only weakly correlated with g. This study sought to replicate the pitch discrimination findings and to expand them to the modality of color discrimination in a large sample (N = 899) by correlating two sensory discrimination measures with the general factor from a battery of 13 cognitive-ability tests. The modest correlations found between g and measures of pitch discrimination (r =.21) and color discrimination (r =.31) suggest that sensory discrimination is relatively distinct from general intelligence. Although consistent with the neural processing speed explanation of g, these results cast doubt on a strong form of the sensory discrimination explanation of g. D