A new quantitative approach to the assessment of stages of vigilance as defined by spatiotemporal EEG patterning

Electroencephalographically oriented research on vigilance needs valid measures for assessing the level of vigilance between wakefulness and sleep. When studying different psychologically, psychopathologically, and pharmacologically induced states, special attention has to be paid to minor alterations of the level of vigilance which are reflected, essentially, in topographical changes of alpha-activity (Stage A). Since vigilance is a dynamic process, brief fluctuations in the range of a few seconds must also be recorded. In our opinion existing methods of quantification do not fully meet these demands. We have, therefore, developed a relatively simple procedure which can be characterized as an attempt quantitatively to reconstruct visually, i.e., spatiotemporally defined patterns of vigilance. The usefulness of this method, which also has certain limitations, has been demonstrated in psychopharmacological studies.     

Effect of directed attention on cerebral asymmetries in stuttering adults

9 stutterers and 9 nonstutterers were administered a dichotic digits test under conditions of free recall and directed attention. Analysis indicated right-ear preference for both groups and no differences between the free recall and directed listening conditions. Results are discussed in relation to previous studies in which dichotic digit-stimuli were presented to stutterers.     

Children's perception of parental exercise: influence of sex and age

The purpose of the study was to document children's perception of parental exercise, relating these perceptions to (1) the self-reported parents' habits of exercise, and (2) the children's own activity patterns. The subjects were 198 students of both sexes, aged 12 to 14 yr. and enrolled in school Grades 7 to 9. A standard questionnaire assessed their perceptions of parental and personal physical activity. Both parents of each subject also reported their respective levels of habitual physical activity. Congruence between the children's perceptions and the self-reported exercise habits of the opposite-sex parent differed for boys and girls, increasing for boys and decreasing for girls between Grades 7 and 9. No significant associations were observed between the children's perception of parental exercise patterns and their own like habits. This suggests that during adolescence parental influences are minimized by other factors, personal or environmental.     

Locus of inhibition effects in the priming of lexical decisions: pre- or postlexical access?

The lexical decision task has been employed to investigate the effects of semantic context on word recognition. A frequent finding from the task is that “word” responses are slower when the target is preceded by an unrelated word than when it is preceded by a neutral stimulus. This inhibition effect has been interpreted as indicating that the unrelated prime interferes with word-recognition processes operating on the target. In three experiments, the effects of unrelated primes were compared for a lexical decision and word naming task. Although large inhibition effects were found for the lexical decision task in all experiments, no inhibition effects were observed for the naming task. The results are interpreted as demonstrating that inhibition effects in the lexical decision task are not on recognition processes; rather they are located at processes operating after recognition of the target has occurred.     

Maps between some different kinds of contraction function: The finite case

In some recent papers, the authors and Peter Gärdenfors have defined and studied two different kinds of formal operation, conceived as possible representations of the intuitive process of contracting a theory to eliminate a proposition. These are partial meet contraction (including as limiting cases full meet contraction and maxichoice contraction) and safe contraction. It is known, via the representation theorem for the former, that every safe contraction operation over a theory is a partial meet contraction over that theory. The purpose of the present paper is to study the relationship more finely, by seeking an explicit map between the component orderings involved in each of the two kinds of contraction. It is shown that at least in the finite case a suitable map exists, with the consequence that the relational, transitively relational, and antisymmetrically relational partial meet contraction functions form identifiable subclasses of the safe contraction functions, over any theory finite modulo logical equivalence. In the process of constructing the map, as the composition of four simple transformations, mediating notions of bottom and top contraction are introduced. The study of the infinite case remains open.     

Latent trait models and dichotomization of graded responses

This paper discusses thecompatibility of the polychotomous Rasch model with dichotomization of the response continuum. It is argued that in the case of graded responses, the response categories presented to the subject are essentially an arbitrary polychotomization of the response continuum, ranging for example from total rejection or disagreement to total acceptance or agreement of an item or statement. Because of this arbitrariness, the measurement outcome should be independent of the specific polychotomization applied, for example, presenting a specific multicategory response format should not affect the measurement outcome. When such is the case, the original polychotomous model is called compatible with dichotomization.A distinction is made between polychotomization or dichotomization before the fact, that is, in constructing the response format, and polycho- or dichotomization after the fact, for example in dichotomizing existing graded response data.It is shown that, at least in case of dichotomization after-the-fact, the polychotomous Rasch model is not compatible with dichotomization, unless a rather special condition of the model parameters is met. Insofar as it may be argued that dichotomization before the fact is not essentially different from dichotomization after the fact, the value of the unidimensional polychotomous Rasch model is consequently questionable. The impact of our conclusion on related models is also discussed.     

A family of chance-corrected association coefficients for metric scales

A chance-corrected version of the family of association coefficients for metric scales proposed by Zegers and ten Berge is presented. It is shown that a matrix with chance-corrected coefficients between a number of variables is Gramian. The members of the chance-corrected family are shown to be partially ordered. The author is obliged to Jos ten Berge for helpful comments.     

Interpersonal dominance and coronary prone behavior

Type A “coronary-prone behavior” is a risk factor for coronary artery and heart disease. Questionnaire research indicates that interpersonal dominance is one of the strongest behavioral correlates of the Type A behavior pattern, although little effort has been made to demonstrate a link between the behavioral manifestations of interpersonal dominance and Pattern A responding. This study was conducted to establish such a link. All possible combinations of extreme As (N = 42) and Bs (N = 42) were matched in dyads that negotiated extreme bipolar opposite positions on a “teacher dismissal” issue. Analysis of process and outcome behaviors suggested that type A individuals are unilaterally more dominant than their Type B counterparts. Possible physiological mechanisms mediating dominance and cardiovascular disease are discussed.