Distortions and fluctuations in topographic memory

Two experiments dealing with, the learning of a space by map or by navigation approached the questions of equivalency of the cognitive processes involved in spatial information and of response fluctuation. In the first experiment, 11 subjects were asked to situate, six times, 18 lo-cations on a blank map. In the second experiment, the subjects were first given 3 min to learn a map with 12 locations marked, and then asked to reproduce it. The task was repeated six times, using three different maps. This gave us several trials per subject, so that distortion could be distinguished from response fluctuation. In Experiment 1, the range of values was the same for response inaccuracy and response, fluctuation; in Experiment 2, the range was greater for response inaccuracy than for response fluctuation. The results showed that space learning by navigation and space learning by map involve different cognitive processes.     

The dynamics of Prägnanz

Summary There is quite wide-spread agreement about the relevance of pattern Pragnanz (Koffka, 1935) with respect to the human interpretation of visual patterns. There is less agreement about whether pattern Pragnanz is based solely on pattern information (static) or also on the history of the perceiver (dynamic). In Van Leeuwen and Van den Hof (1991), experimental data concerning serial patterns are presented within the framework of the dynamic-network approach initiated by Buffart (1986, 1987). These experimental data are claimed to give evidence against the static-coding approach initiated by Leeuwenberg (1969, 1971). In the present paper, however, I show first that Buffart's theoretical basis is incorrect, and that in fact Leeuwenberg's static-coding approach is the basis for the dynamic-network approach. Second, I show that those experimental data rather give evidence in favor of the static-coding approach, by using those same data for a test of the most recent static-coding model (Van der Helm & Leeuwenberg, 1991; Van der Helm, Van Lier, & Leeuwenberg, 1992). Finally, I propose a reconciliation between the two approaches, in the sense that the dynamic-network model could be shaped in such a way that it yields a simulation, and maybe even an enrichment, of the static-coding model.     

Computing Cohen’s kappa coefficients using SPSS MATRIX

This short paper proposes a general computing strategy to compute Kappa coefficients using the SPSS MATRIX routine. The method is based on the following rationale. If the contingency table is considered as a square matrix, then the observed proportions of agreement lie in the main diagonal’s cells, and their sum equals the trace of the matrix, whereas the proportions of agreement expected by chance are the joint product of marginals. The generalization to weighted kappa, which requires an additional square matrix of disagreement weights, both matrices having the same order, becomes possible by the use of the Hadamard product-that is, the elementwise direct product of two matrices.     

Resetting the pitch-analysis system: 1. Effects of rise times of tones in noise backgrounds or of harmonics in a complex tone

The question of whether sudden increases in the amplitude of pure-tone components would perceptually isolate them from a more complex spectrum was investigated in two experiments. In Experiment 1, a 3.5-sec noise was played as a masker. During the noise, two pure-tone components of different frequencies appeared in succession. Subjects were asked to judge whether the pitch sequence went up or down. The rise time of these components had only a small and inconsistent effect on discrimination. In Experiment 2, the 3.5-sec background signal was a complex tone. The amplitudes of two of its components were incremented in succession. Again, subjects judged whether the pitch pattern went up or down. This time there was a sizable, monotonic effect of the rise time of the increments, with more rapid increments leading to better discrimination. The difference between the two results is interpreted in terms of the auditory system’s response to changing and unchanging signals and the role of its “sudden-change” responses in attracting perceptual processing to certain spectral regions.     

A compensatory approach to optimal selection with mastery scores

A Bayesian approach for simultaneous optimization of test-based decisions is presented using the example of a selection decision for a treatment followed by a mastery decision. A distinction is made between weak and strong rules where, as opposed to strong rules, weak rules use prior test scores as collateral data. Conditions for monotonicity of optimal weak and strong rules are presented. It is shown that under mild conditions on the test score distributions and utility functions, weak rules are always compensatory by nature. The authors are indebted to Wilbert Kallenberg for his valuable comments and to Jan Gulmans for providing the data for the empirical example. The names of the authors are alphabetical; they are equally responsible for the contents of this paper.     

Forms of Authority and the Real Ad Verecundiam

This paper provides a typology of appeals to authority, identifying three distinct types: that which is based on a command; that which is based on expertise; and that which is based on dignity. Each type is distinguished with respect to the reaction that a failure to follow it ordinarily evokes. The rhetorical roots of Locke's ad verecundiam are traced to the rhetorical practices of ancient Rome.     

Political periodicals in policy formation

This is an ethnographic report on a conference entitled “The Politics of Publishing” which featured editors and writers from leading magazines and journals of political opinion. The aim of the conference was to articulate the intellectual ground on which each publication is predicated. A further goal of these observations was to seek out a common ground, a consensual series of assumptions, that permits such journals and their leading participants to flourish amidst conflict and opposing viewpoints. The article is less a study of the relationship of knowledge and policy, as such, as much as it is a study of the weaker forms of these terms, namely, information and ideology. These remarks are thus intended as a contribution to the elite impact on mass public opinion at one level, and the cornucopia of political ideas at a somewhat more abstract level. He also serves as Chairman of the Board of Transaction Publishers, located at Rutgers University, New Brunswick, NJ, USA 08903.     

A Grammatical Specific Language Impairment in Children: An Autosomal Dominant Inheritance?

The aim of this study is to provide further characterization of a subgroup of so-called “Grammatical specific language-impaired (SLI)” children. The Grammatical SLI children have a persistent and disproportionate impairment in grammatical comprehension and expression of language. Previous research has indicated that their language impairment may be characterized by a domain-specific and modular language deficit. This study provides an initial investigation as to whether there is a genetic basis underlying their disorder as has been found for other forms of SLI and for SLI in general. The incidence of familial aggregation of language impairment was investigated in 12 Grammatical SLI children (aged 9:3 to 12:10). A familial language impairment (LI) history was classified as positive if one or more of the probands' relatives had a history of a speech/language or reading/writing problem which required speech therapy or any other form of remedial help. Case history information provided an initial indication that the Grammatical SLI children had a significantly higher incidence of a positive familial LI history than could be expected by chance. A questionnaire provided evidence of a positive LI history in the first-degree relatives of the SLI probands and 49 normally developing control probands. The SLI probands had a clearly and significantly higher incidence of a positive familial LI history than the control probands (77.8 vs. 28.5%, respectively). The results are consistent with a genetic basis underlying Grammatical SLI. The pattern of impairment in the SLI probands' relatives is consistent with an autosomal dominant genetic inheritance. In contrast to the control probands, the SLI probands' impaired relatives did not show a male gender bias. Thus, the gene does not appear to be sex-linked. The data indicate that further research is warranted to investigate the nature of the LI in the relatives of the Grammatical SLI probands and the genetic characteristics of this subgroup. The implications for the biological, domain-specific, and modular bases to language are discussed.