Classification of empirically derived prototypes as a function of category experience

In three experiments, subjects learned to classify dot patterns into three categories represented by either three, six, or nine exemplars. Following learning, subjects were tested on an additional set of patterns, which included patterns from the learning phase, the category objective prototypes, and new distortions of the objective prototypes. Also included in the test set were empirical prototypes and distortions of empirical prototypes. Empirical prototypes were derived by averaging feature values of category exemplars in the learning phase. The overall results revealed that empirical prototypes were classified more accurately than were objective prototypes. In addition, a pattern of convergence in error rates was observed for distortions of the objective and empirical prototypes as category set size increased, but this same pattern was not observed for the objective and empirical prototypes themselves. This lack of convergence for the prototypes is inconsistent with explanations of the category set size effect that rely on the central limit theorem.     

The role of phonemes and syllables in the perceived similarity of speech sounds for children

In two experiments, we investigated the factors that influence the perceived similarity of speech sounds at two developmental levels. Kindergartners and second graders were asked to classify nonsense words, which were related by syllable and phoneme correspondences. The results support the existence of a developmental trend toward increased attention to individual phonemic segments. Moreover, one significant factor in determining the perceived similarity of speech sounds appears to be the position of the component correspondences; attention to the beginning of utterances may have developmental priority. An unexpected finding was that the linguistic status of the unit involved in a correspondence (whether it was a syllable or a phoneme) did not seem particularly important. Apparently, the factors which contribute to the perceived similarity of speech sounds in the classification task are not identical to those which underlie performance in explicit segmentation and manipulation tasks, since in the latter sort of task, syllables are more accessible than phonemes for young children. The present task may tap a level of processing that is closer to the one entailed in word recognition and lexical access.     

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.     

Some modifications of Scott's theorem on injective spaces

D. Scott in his paper [5] on the mathematical models for the Church-Curry -calculus proved the following theorem.A topological space X. is an absolute extensor for the category of all topological spaces iff a contraction of X. is a topological space of Scott's open sets in a continuous lattice.In this paper we prove a generalization of this theorem for the category of , -closure spaces. The main theorem says that, for some cardinal numbers , , absolute extensors for the category of , -closure spaces are exactly , -closure spaces of , -filters in , >-semidistributive lattices (Theorem 3.5).If = and = we obtain Scott's Theorem (Corollary 2.1). If = 0 and = we obtain a characterization of closure spaces of filters in a complete Heyting lattice (Corollary 3.4). If = 0 and = we obtain a characterization of closure space of all principial filters in a completely distributive complete lattice (Corollary 3.3).     

On decidable consequence operators

The main theorem says that a consequence operator is an effective part of the consequence operator for the classical prepositional calculus iff it is a consequence operator for a logic satisfying the compactness theorem, and in which every finitely axiomatizable theory is decidable.     

Identification with an aggressor or a victim and its relation to creativity

Studied identification using a meta-contrast design. The first stimulus was the word 'I'. The second stimulus depicted an aggressor and a victim facing each other. The subliminal 'I' was flashed on either the victim or on the aggressor, or completely withheld. The subjects were 33 school children, aged 10–12 years. They also took a percept-genetic (PG) test of creativity, measuring willingness to return to and recognize early conceptions of a stimulus picture (a still-life). The results showed that the creative children reacted with less anxiety and defense when manipulated to identify with the aggressor than with the victim. The uncreative children showed the opposite reaction, namely a preference for the passive, surrendering victim.     

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.     

Controversies and existence claims in chemistry: The theory of resonance

Controversies, i.e., multiple theory confrontations, may have a strong impact on the development of science. By an analysis of the so-called “resonance controversy” in chemistry the view that controversies and their resolution differ considerably from the process of theory succession is defended. It is argued that controversies are symptomatic of foundational problems, produce theory-scattering or domain-splitting, and induce ontological shifts. An explication is given of the role of existence claims and the applicability of Ockham's Razor in the resolution of controversies. The requirement of a realistic interpretation of theories at all times, as defended by some philosophers, is criticised.