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.     

Effects of auditory masking by white noise on primary stressing during spontaneous speech

6 adult subjects (3 men, 3 women) produced highly similar spontaneous speech utterances in quiet and with 90-dB SPL white noise. The frequency of occurrence of perceptual judgments of primary stressing in an utterance was not affected by the masking noise. This finding supplements our previous report that variability for stress production of fundamental frequency (fo) during spontaneous speech was preserved under short-term auditory disruption. Also, it adds further support to the contention that fo is under open-loop regulation.     

Effect of moderate doses of alcohol on simple auditory reaction time in a vigilance setting

An experiment was performed with 11 voluntary male subjects to test the effects of moderate doses of alcohol on simple auditory RT in a vigilance setting. Subjects were tested during a 30-min. session, during which signals were presented with an average intersignal interval of 3.75 sec. Subjects responded by pressing a microswitch held in the preferred hand. Analysis indicated that absolute means increased as a function of alcohol dose. With time-on-task alcohol produced a faster increase in RT and especially affected the longest RTs. Number of extreme long reactions (blockings) and mean duration of these reactions increased under alcohol and were directly related to time on task; alcohol produced a much faster increase in number of blockings with time on task. Results were discussed in terms of attentional processes and habituation theory. Some practical implications of the results were pointed out.     

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.     

Context-dependent effects on analogical transfer

The role of context in facilitating analogical transfer was investigated in two experiments. In both experiments, subjects first read two stories that were analogous to Duncker’s (1945) radiation problem. Later, subjects attempted to solve the radiation problem. In Experiment 1, the radiation problem was presented in a different context than that of the stories, and followed them by 6 min. Transfer was observed in subjects who were prompted to use the earlier stories in solving the problem. However, the solution frequency of subjects not given such prompts did not differ from control levels. In Experiment 2, the radiation problem was presented in the same context as the earlier stories to some subjects, and in a different context to others. The timing of the radiation problem also was varied. When a 6-min interval separated the stories from the radiation problem, transfer was a function of context, with weak transfer being observed in the samecontext condition, and no transfer being observed in the different-context condition. At a 45-sec delay, transfer was again observed in the same~ontext condition, and a nonsignificant trend toward transfer was observed in the different-context condition. The results were interpreted as indicating that context facilitates the retrieval of relevant problem-solving schemas, and as suggesting that the possession of relevant schemas is not sufficient to produce analogical transfer.     

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.