The influence of pyrithioxine on certain factors of intelligence

A double-blind trial with pyrithioxine was made with 22 pairs of visually handicapped children who were equal in IQ scores and in chronological age. Although an improvement of abstraction ability was noticed, the overall results were not in concurrence with the general tendency in relevant literature.This paper is an abstract from a master's thesis in psychology submitted to the University of Stellenbosch.     

Der ‚intentionale Fehlschluß‘ — ein Dogma?

Journal for General Philosophy of Science -     

Electroneurographic and electroencephalographic findings is patients exposed to hexachlorcyclohexane

While the health of the general population is not adversely affected by the exposure the pesticides in food and environment, workers, who have during their occupation been intensely exposed to pesticides, exhibit a higher prevalence of slight neurotoxic symptoms. In the present study the electroencephalograms of 3 of a group 10 workmen, who had been continually exposed to hexachlorcyclohexane, show pathological findings. The electromyograms of 8 of these 10 workman demonstrate a disturbance of the peripherical motoneuron. All probands, who exhibit o pathological EEG, also show a polyneuropathy.     

Basal ganglia participation in language pathology

Language disturbances were studied in 40 patients with well-demarcated vascular lesions of the speech-dominant hemisphere. Computerized cranial tomography was used for localization of the lesion. Special emphasis was given to the analysis of automatized speech and repetitive verbal phenomena.Subcortical infarctions with basal ganglia involvement led to transient aphasia although long-lasting abnormalities of language could be detected in these patients. Aphasia was more severe if a cortical lesion was combined with a basal ganglia lesion. Automatisms and recurring utterances occurred only with combined cortical and basal ganglia lesions. A lesion of Wernicke's area alone, without involvement of prerolandic structures or subcortical nuclei, was sufficient to produce long-lasting aphasia, whereas lesions of Broca's area alone produced only transient language disturbances. The results are compatible with a recent theory of multiple cerebral representation of function.     

Irrational Cognitions and the Fear of Flying

In order to test the hypothesis that the fear of flying is associated with irrational evaluative beliefs, as postulated by Rational Emotive Behavior Therapy for anxiety disorders, 15 fearful flyers and 7 non-fearful flyers participated in the Articulated Thoughts during Simulated Situations procedure. Six experimental scenes depicting some basic fears associated with the fear of flying and six supposedly non-anxiety provoking flight-related control scenes were used. The fear of flying group displayed significantly more irrational thoughts and significantly higher subjective ratings of anxiety on all experimental and five control scenes compared to the non-fearful flyers. Their negative cognitions were predominantly characterized by awfulizing and low frustration tolerance. The results are interpreted as offering support for the cognitive view that anxiety, and the fear of flying, are associated with negative cognitions characterized by a preoccupation with danger and with an overestimation of the seriousness of the perceived threat (awfulizing) and an underestimation of coping abilities (low frustration tolerance).     

Zitierte zeichenreihen

We use quotation marks when we wish to refer to an expression. We can and do so refer even when this expression is composed of characters which do not occur in our alphabet. That's why Tarski's, Quine's, and Geach's theories of quotation don't work. The proposals of Davidson, Frege, and C. Washington, however, do not provide a plausible account of quotation either. The problem is to construct a Tarskian theory of truth for an object language which contains quotation marks, without appealing to quotation marks in the metalanguage. I propose to supply Tarski's truth definition with an axiom which determines the denotation of all expressions containing quotation marks. According to this axiom, quotation marks create a non-extensional context. Since our admitting such contexts does not lead to any difficulties in our recursive truth characterization, we may indeed dispense with extensionalism. Finally, I argue that we classify and denote expressions in the very same way that we classify and denote extralinguistic entities.     

Words in the brain's language

If the cortex is an associative memory, strongly connected cell assemblies will form when neurons in different cortical areas are frequently active at the same time. The cortical distributions of these assemblies must be a consequence of where in the cortex correlated neuronal activity occurred during learning. An assembly can be considered a functional unit exhibiting activity states such as full activation ("ignition") after appropriate sensory stimulation (possibly related to perception) and continuous reverberation of excitation within the assembly (a putative memory process). This has implications for cortical topographies and activity dynamics of cell assemblies forming during language acquisition, in particular for those representing words. Cortical topographies of assemblies should be related to aspects of the meaning of the words they represent, and physiological signs of cell assembly ignition should be followed by possible indicators of reverberation. The following postulates are discussed in detail: (1) assemblies representing phonological word forms are strongly lateralized and distributed over perisylvian cortices; (2) assemblies representing highly abstract words such as grammatical function words are also strongly lateralized and restricted to these perisylvian regions; (3) assemblies representing concrete content words include additional neurons in both hemispheres; (4) assemblies representing words referring to visual stimuli include neurons in visual cortices; and (5) assemblies representing words referring to actions include neurons in motor cortices. Two main sources of evidence are used to evaluate these proposals: (a) imaging studies focusing on localizing word processing in the brain, based on stimulus-triggered event-related potentials (ERPs), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI), and (b) studies of the temporal dynamics of fast activity changes in the brain, as revealed by high-frequency responses recorded in the electroencephalogram (EEG) and magnetoencephalogram (MEG). These data provide evidence for processing differences between words and matched meaningless pseudowords, and between word classes, such as concrete content and abstract function words, and words evoking visual or motor associations. There is evidence for early word class-specific spreading of neuronal activity and for equally specific high-frequency responses occurring later. These results support a neurobiological model of language in the Hebbian tradition. Competing large-scale neuronal theories of language are discussed in light of the data summarized. Neurobiological perspectives on the problem of serial order of words in syntactic strings are considered in closing.     

Local and global orientation in visual search

Six experiments investigated the role of global (shape) and local (contour) orientation in visual search for an orientation target. Experiment 1 demonstrated thatsearch for a conjunction of local contours with a distinct global orientation was less efficient than search for a target featurally distinct in terms of both global and local contour orientation. However, Experiments 2 and 4 demonstrated that the presence of a unique line contour was neither sufficient nor necessary to allow efficient search. Experiment 5 found thatsearch for a local orientation difference was strongly impeded by irrelevant variation in global orientation, arguing for a preeminent role for global orientation. Finally, Experiment 6 demonstrated that the orientation search asymmetry holds for the global orientation of stimuli. Taken together, the results are consistent with visual search processes guided predominately by a representation of global orientation.