To be and not to be: Dialectical tense logic

The paper concerns time, change and contradiction, and is in three parts. The first is an analysis of the problem of the instant of change. It is argued that some changes are such that at the instant of change the system is in both the prior and the posterior state. In particular there are some changes from p being true to p being true where a contradiction is realized. The second part of the paper specifies a formal logic which accommodates this possibility. It is a tense logic based on an underlying paraconsistent prepositional logic, the logic of paradox. (See the author's article of the same name Journal of Philosophical Logic 8 (1979).) Soundness and completeness are established, the latter by the canonical model construction, and extensions of the basic system briefly considered. The final part of the paper discusses Leibniz's principle of continuity: Whatever holds up to the limit holds at the limit. It argues that in the context of physical changes this is a very plausible principle. When it is built into the logic of the previous part, it allows a rigorous proof that change entails contradictions. Finally the relation of this to remarks on dialectics by Hegel and Engels is briefly discussed.     

Consistency and error in motor performance

Two response measures that described the consistency and accuracy of motor performance were investigated. A pursuit tracking task was used as the vehicle whereby changes in perceptual motor performance could be monitored over several learning trials. The intra-individual variability of a subject's tracking response was compared to the root mean squared error that was accumulated during each block of trials. Whereas both response measures were sensitive to the changes in performance that occured as a result of practice, neither could be considered sufficiently informative as to be used as a sole indicator of skill acquisition. It appears that both consistency and error measures are needed to describe the subjects' performance as they acquire a perceptual motor skill.     

Second-order ‘fear’ conditioning in humans: Persistence of CR2 following extinction of CR1

Two groups of subjects were given pairings of a slide of a triangle (CS₁) with an aversive loud noise (US). After first-order conditioning a different figure (CS₂⁺) was paired with CS₁, whilst a third figure acted as a non-paired control (CS₂⁰). Conditioned second-order skin conductance responses (SCRs) were established to CS₂⁺ for all subjects who had undergone first-order conditioning. Following second-order conditioning, SCRs to CS₁ were extinguished and CS₂⁺ was subsequently tested for retention of its SCR evoking properties. For the group of subjects who believed they had an avoidance response available during the second-order conditioning phase, CR₂ failed to survive extinction of CR₁. However, for the group of subjects who had no perceived control over US presentation, extinction of cr₁ did not eliminate CR₂. This latter finding is consistent with associative analyses of second-order conditioning in animals and has clinical implications for the treatment of fear-related problems.     

An application of a biased version of the Bradley-Terry-Luce model to professional basketball results

Some extensions of the Bradley-Terry-Luce model for paired comparisons are presented and used to assess the existence of a home court advantage for professional basketball teams. It is shown how maximum likelihood estimates for these models can be obtained from a simple iterative scaling algorithm. Won-loss records for the regular season are used to make predictions for playoff series. The models are extended to include possible differences among divisions. These models can be applied in many other situations to incorporate group effects and order effects into analysis of paired comparisons.     

Recognizing faces in and out of context

Two experiments are reported which examined the influence of context on face recognition accuracy for novel and familiar faces respectively. Context was manipulated by varying the physical background against which the faces appeared. In Experiment I, 80 student subjects observed 18 faces before attempting to recognize them in a sequence of 36 alternatives. For half the subjects, the backgrounds changed from study to test, while for the remainder they stayed the same. In addition, for half the subjects, both the pose and expression of the face also changed, while for the others it remained constant. Changes in pose plus expression and context significantly reduced recognition accuracy for the target faces. Experiment II used an identical design, except that the faces of celebrities replaced the novel faces. The influence of context was eliminated but the effects of pose and expression were maintained. However, when only faces which were actually identified by subjects were considered, the effects of pose and expression, too, were eliminated. The significance of these findings for theories of contextual memory are discussed.     

Some problems of Wilson's disease

The Leipzig Center for Wilson's Disease in the GDR is charged with the registration and diagnosis of all homozygous Wilson gene carriers, the clarification of all suspected cases, including the heterozygote test, and the co-ordination of long-term treatment. At present, there are 78 recorded Wilson gene carriers living. On the basis of our own comprehensive observations and investigations over prolonged periods of time, questions concerning pathogenesis, genetics, diagnosis and therapeutic measures, including their side-effects, are dealt with.     

A new Visual Aesthetic Sensitivity Test (VAST): II. cross-cultural comparison between England and Japan

A comparison was made of the scores of 171 Japanese boys and 156 Japanese girls, and of 204 English boys and 165 English girls, on the Visual Aesthetic Sensitivity Test. Also compared were 145 male and 163 female Japanese students, with 38 male and 73 female English students. Japanese children had scores significantly higher than English children, while Japanese students had scores significantly lower than English students. There was little evidence of age increments in score for either group of children. Difficulty levels of the 42 item-pairs were very similar in the two cultures, as were internal (split-half) reliabilities. It is concluded that cultural differences between the two countries, as far as visual aesthetic appreciation is concerned, seem at best minimal.     

Facial myokomias in brain stem tumors]

Four cases of brain-stem tumor were described, in which myokymias were electromyographically derived from the region of several cerebral nerves. An attempt is made to interpret the effects of twitching by reference to the electromyogram. Myokymias are a positive indication of organic brain stem damage. The use subtle techniques of electromyographic examination shows that this muscular hyperkinesis is not so infrequent a symptom as is generally believed.