Construct Validity of Concepts of Attention in Healthy Controls and Patients with CHI

The present study aimed to examine the construct validity of three aspects of attention, namely focused, divided, and supervisory control of attention. Factor-analytic techniques were applied to scores of healthy subjects on a series of neuropsychological tests tapping these aspects of attention. The two components found did not match the hypothesized aspects and were labeled as Memory-driven Action and Stimulus-driven Reaction. The second question was whether the same components could be found in a group of patients with CHI. The pattern of attentional functions found in healthy subjects had changed qualitatively in patients with CHI. A possible explanation for this result in terms of a shift from automatic to controlled processing is discussed.     

Equity and individual preferences in an MDG

Before participating in an Maximizing Difference Game (MDG) subjects were classified with the help of a social motive test (GDG, Liebrand, 1984) as having a cooperative, an individualistic or a Competitive preference for own/other outcome distributions. Thereafter subjects did make choices in an MDG. A status (high, equal, low, no feedback) × matrix (advantage: 8/6, disadvantage 6/81) × preference (competitive, individualistic, cooperative)-design was employed, whereas one control condition, i.e. equal statuslmatrix equal (616) was added. Equity theory could explain the data rather well. Support was found for the status hypothesis, i.e. high status subjects made more D-choices in an MDG than equal status subjects; equal status subjects made more D-choices than low status subjects, and for the matrix hypothesis, i.e. matrix disadvantage subjects made more D-choices than subjects playing in a matrix advantage position. Equity theory could also explain a significant status × matrix interaction effect. Support was partly found for a preference hypothesis: Competitors made more D-choices than cooperatives, while contrary to the hypothesis, individualists behaved more like competitors.     

Computing maximum likelihood estimates of loglinear models from marginal sums with special attention to loglinear item response theory

In this paper algorithms are described for obtaining the maximum likelihood estimates of the parameters in loglinear models. Modified versions of the iterative proportional fitting and Newton-Raphson algorithms are described that work on the minimal sufficient statistics rather than on the usual counts in the full contingency table. This is desirable if the contingency table becomes too large to store. Special attention is given to loglinear IRT models that are used for the analysis of educational and psychological test data. To calculate the necessary expected sufficient statistics and other marginal sums of the table, a method is described that avoids summing large numbers of elementary cell frequencies by writing them out in terms of multiplicative model parameters and applying the distributive law of multiplication over summation. These algorithms are used in the computer program LOGIMO. The modified algorithms are illustrated with simulated data. The author thanks Wim J. van der Linden, Gideon J. Mellenberh and Namburi S. Raju for their valuable comments and suggestions.     

Social psychological research in The Netherlands, 1980-1988

This paper contains an investigation about research of Dutch social psychologists. Based on reported publications two types of analyses were performed. The reported publications were categorized by means of a topic-inventory proposed by Fisch and Daniel (1982), which enabled us to compare Dutch trends with developments in Europe and the U. S.A. Moreover, by means of bibliometric analyses publications of Dutch social psychologists were related to data obtained by the Institute for Scientific Information (ISI). Several trends were observed and discussed.     

Prototypicality of arguments and conformity to ingroup norms

Social categorization is claimed to elicit a tendency to conform to ingroup norms, which may result in attitude change after exposure to information on the opinions of other ingroup members. It was hypothesized that the degree to which arguments represented ingroup norms, i.e., were prototypical, would affect their potential influence on attitudes, such that prototypical arguments would be perceived as being of higher quality and would elicit more attitude change. Moreover, prototypical arguments were expected to elicit more argument elaboration. Two experiments were designed to test these predictions. In Experiment 1 subjects were exposed to both a set of pro and a set of contra arguments, while one of the sets was allegedly prototypical of ingroup attitudes. In Experiment 2 subjects were exposed to either prototypical or a-prototypical pro or contra arguments allegedly originating from in- or outgroup. In both studies conformity to ingroup norms was observed. In addition, prototypical ingroup arguments elicited higher quality ratings in the first study. Indications of higher elaboration of prototypical ingroup arguments were found.     

Clamped Corticosterone (B) Reveals the Effect of Endogenous B on Both Facilitated Responsivity to Acute Restraint and Metabolic Responses to Chronic Stress

To determine the effects of both corticosterone (B) and chronic stressors on acute ACTH responses to restraint, young male rats were exposed to streptozotocin-induced diabetes, cold (5-7 degreesC) or intracerebroventricular (icv) neuropeptide Y (NPY) for 5 d and then exposed to restraint within 2 h after lights on. Two groups of rats were studied: intact and adrenalectomized replaced with B pellets that maintained plasma B in the normal mean 24-h range of intact rats. In addition to ACTH and B responses to restraint on d 5, body weight, food intake, fat depots, glucose and other hormones were measured to determine the role of stress-induced elevations in B on energy balance. ACTH responses to restraint were normal in intact rats subjected to diabetes or cold. By contrast, there was no ACTH or B response to restraint in NPY-infused intact rats. All 3 groups of chronically stimulated adrenalectomized rats with clamped B had facilitated ACTH responses to restraint compared to their treatment controls. Overall food intake increased in all groups of stressed rats; however, augmented intake occurred only during the light in intact rats and equally in the light and dark in B-clamped rats. White adipose depot weights were decreased by both diabetes and cold and increased by NPY in intact rats; the decreases with cold and increases with NPY were both blunted and changes in fat stores were not significant in adrenalectomized, B-clamped rats. We conclude that: 1. diabetes- and cold-induced facilitation of restraint-induced afferent input to hypothalamic control of the hypothalamo-pituitary-adrenal (HPA) axis is opposed in intact rats by the elevated feedback signal of B secretion; 2. NPY does not induce facilitation of afferent stress pathways; 3. chronic stimulation of the HPA axis induces acute hyperresponsiveness of hypothalamic neurons to restraint provided that the afferent input of this acute stimulus is not prevented by B feedback; 4. stimulus-induced elevations in B secretion result in day-time feeding; 5. insensitivity of both caloric efficiency and white fat stores to chronic stress in adrenalectomized, B-clamped rats results from loss of normally variable B levels.     

Self-reported cognitive failures and neurotic symptomatology

Three studies examined the Cognitive Failures Questionnaire (CFQ) and its psychopathological correlates. In Study 1, the psychometric qualities of the Dutch translation of the CFQ were evaluated in a student sample. Internal consistency and test-retest stability were found to be satisfactory. Furthermore, CFQ was positively correlated with anxiety symptoms, even when the influence of traditional trait variables (i.e., neuroticism and trait anxiety) was partialled out. Study 2 examined the CFQ as a predictor of treatment outcome in spider phobia. No evidence was found to suggest that high CFQ scores are associated with a less favourable treatment outcome. Also, spider phobics had CFQ scores in the normal range. Study 3 evaluated the CFQ in a mixed sample of anxiety disordered and depressive outpatients. Depressive patients, but not anxiety disordered patients, were found to have heightened CFQ scores. Overall, CFQ scores were positively associated with symptom severity. Yet, there were no indications that patients with high CFQ scores profit less from treatment than those with low CFQ scores. Taken together, the results provide support for the view that the CFQ taps daily cognitive routines that are undermined by anxiety and depression. However, the findings do not point to the CFQ being a cognitive vulnerability measure that is related to treatment success.     

Maximization of sums of quotients of quadratic forms and some generalizations

Monotonically convergent algorithms are described for maximizing six (constrained) functions of vectors x, or matricesX with columns x₁, ..., x _r . These functions are h₁(x)= _k (xA _kx)(xC _kx)^–1, H₁(X)= _k tr (XA _k X)(XC _k X)^–1, h₁(X)= _{k l} (x _l A _kx _l ) (x _l C _kx _l )^–1 withX constrained to be columnwise orthonormal, h₂(x)= _k (xA _kx)²(xC _kx)^–1 subject to xx=1, H₂(X)= _k tr(XA _kX)(XA_kX)(XC_kX)^–1 subject toXX=I, and h₂(X)= _{k l} (x _l A _kx _l )² (x _l C _kX _l )^–1 subject toXX=I. In these functions the matricesC _k are assumed to be positive definite. The matricesA _k can be arbitrary square matrices. The general formulation of the functions and the algorithms allows for application of the algorithms in various problems that arise in multivariate analysis. Several applications of the general algorithms are given. Specifically, algorithms are given for reciprocal principal components analysis, binormamin rotation, generalized discriminant analysis, variants of generalized principal components analysis, simple structure rotation for one of the latter variants, and set component analysis. For most of these methods the algorithms appear to be new, for the others the existing algorithms turn out to be special cases of the newly derived general algorithms.This research has been made possible by a fellowship from the Royal Netherlands Academy of Arts and Sciences to the author. The author is obliged to Jos ten Berge for stimulating this research and for helpful comments on an earlier version of this paper.     

The anthropological tradition in the philosophy of medicine

The tradition of anthropological medicine in philosophy of medicine is analyzed in relation to the earlier interest in epistemological issues in medicine around the turn of the century as well as to the current interest in medical ethics. It is argued that there is a continuity between epistemological, anthropological and ethical approaches in philosophy of medicine. Three basic ideas of anthropologically-oriented medicine are discussed: the rejection of Cartesian dualism, the notion of medicine as science of the human person, and the necessity of a comprehensive understanding of disease. Next, it is discussed why the anthropological movement has been superseded by the increasing interest in medical ethics. It is concluded that the present-day moral issues cannot be interpreted and resolved without clarification of the underlying anthropological images.