Ordinary Objects and Series‐Style Answers to the Special Composition Question

The special composition question asks, roughly, under what conditions composition occurs. The common sense view is that composition only occurs among some things and that all and only ‘ordinary objects’ exist. Peter van Inwagen has marshaled a devastating argument against this view. The common sense view appears to commit one to giving what van Inwagen calls a ‘series‐style answer’ to the special composition question, but van Inwagen argues that series‐style answers are impossible because they are inconsistent with the transitivity of parthood. In what follows I answer this objection in addition to other, less troubling objections raised by van Inwagen.     

Norm-of-reaction: definition and misinterpretation of animal research

The development of a phenotype is due to an interaction of the genotype with the environment. Two terms have been used to describe the outcome of this interaction, the norm-of-reaction and the reaction range. The first represents the theoretically limitless distribution of the phenotypes that may be expressed by a given genotype. The reaction range implies an upper and lower limit for phenotype expression possible from a given genotype. A critical distinction between the reaction range and the norm-of-reaction is that the norm-of-reaction is a statement of the conceivable interactions found but does not imply any predictability other than that within the conditions previously tested experimentally, that is, the tails of a normal distribution are infinitely variable, whereas the concept of reaction range implies a limitation inherent in the genotype, that is, a finite range. Empirical support for the reaction-range concept is questionable. Animal studies cited in support of the reaction range have been inappropriately and incorrectly interpreted.     

INFLUENCE OF ASSESSMENT CENTER METHODS ON ASSESSORS'RATINGS

Recently a number of authors have argued persuasively that performance ratings are influenced to a large extent by the way the rater selects, organizes, stores, and recalls information. Although the influence of the rater's cognitive processes on the obtained ratings has been considered in the job-performance evaluation literature, this issue has not been considered in the assessment center literature. The purpose of the present study was to examine how assessment center methods affect the way assessors organize and process assessment center information and affect the ratings they make. Independent groups of assessors underwent one of two methods for evaluating candidates in an assessment center. Data indicated differences in the convergent and discriminant validities and differences in the factor structures of the ratings for the two methods. The pattern of results suggested that the two methods for evaluating assessment center candidates affected the way the assessors organized the assessment center information and affected the obtained ratings. Future research should consider assessment center methods and assessors as sources of variation in assessment center ratings.     

A LONGITUDINAL ANALYSIS OF BIOGRAPHICAL SUBGROUPS USING OWENS' DEVELOPMENTAL-INTEGRATIVE MODEL

The study examined the differential validity of 20 male and 14 female biographical subgroups in terms of 12 factor analyzed dimensions of postcollege experience. Owens' Developmental-Integrative Model hypothesizes that different subgroups of individuals with similar within-group early life experiences should exhibit significant differences (between-group) in a wide variety of life experiences. A sample of 1428 first-year college students were statistically grouped into 23 male and 15 female biodata subgroups after completing a standardized 118-item biodata form (Owens, 1968). Seven years later, a 97-item post-college experience inventory obtained scores for 484 of the original subjects on 12 factors of post-college behavior including job satisfaction, transition from college, personal and marital adjustment, and others. Significant univariate and multivariate differences were found between the biodata subgroups across the 7-year period. Implications for the validity of the D-I model are offered.     

Attenuation of Hippocampal 11beta-Hydroxysteroid Dehydrogenase Type 1 by Chronic Psychosocial Stress in the Tree Shrew

11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD-1) catalyses the interconversion of active cortisol and corticosterone with inert cortisone and 11-dehydrocorticosterone, thus regulating glucocorticoid access to intracellular receptors. In rats, chronic glucocorticoid excess or stress increases 11beta-HSD-1 in the hippocampus, producing suggestions that it may attenuate the deleterious effects of chronic glucocorticoid excess. However, 11beta-HSD-1 predominantly catalyses 11beta-reduction in the intact liver and hippocampal cells, thus regenerating active glucocorticoids from inert substrate. We studied 11beta-HSD activity in the tissues of male tree shrews following 28 days of sustained psychosocial stress or exogenous administration of cortisol. In the hippocampus, chronic psychosocial stress attenuated 11-HSD-1 activity (69 +/- 9% of control), whereas cortisol alone had no effect. In the liver, both chronic stress and cortisol administration decreased 11beta-HSD-1 activity (47 +/- 11% and 49 +/- 4% fall, resp.). Attenuation of 11beta-HSD-1 within tissues may reflect a homeostatic mechanism designed to minimise the adverse effects of prolonged stress and/or glucocorticoid excess.