Item recognition with automatized performance

A theory for automatized performance in item recognition tasks is outlined. Automation occurs during practice with consistent mappings of stimuli to responses. Automatized processing at stages of pattern recognition, binary coding, and response evocation is described in sufficient detail to provide a qualitative explanation for (a) extant data on transfer of training (where previous theories fail), ( b ) known effects of visual confusability and positive set size, and (c) null effect of negative set size (demonstrated in Experiment 1). The effects of visual confusability and positive set size are ascribed to the stage of pattern recognition; it is suggested that their joint effects on reaction times and error rates (measured in Experiment 2) be explained at a quantitative level by a parallel random walk recognition model.     

A comparison between the Grid Test of Schizophrenic Thought Disorder and diagnostic psychologicaI testing

Abstract.— Bannister and Fransella's Grid Test of Schizophrenic Thought Disorder based on Personal Construct Theory and the concept of "loosened construing", as measurable in the scores of Intensity and Consistency between intercorrelations, has been applied to a Scandinavian sample of psychiatric patients. The validity of the test was illustrated, and a significant difference was found between a group of schizophrenics and schizophrenic borderline states and a group without schizophrenic thought disorders. The Grid Test scores were found to agree with thought disorder manifestations as evaluated in qualitative terms on the basis of cognitive and projective tests, but they did not differentiate between developmental levels of thinking corresponding to con-creteness in organic impairment versus diffuseness in schizophrenia. Thus, the concept of "loosened construing" as applied in this thought disorder test seems too unspecific.     

Common mechanisms in apparent motion perception and visual pattern matching

There are close functional similarities between apparent motion perception and visual pattern matching. In particular, striking functional similarities have been demonstrated between perception of rigid objects in apparent motion and purely mental transformations of visual size and orientation used in comparisons of objects with respect to shape but regardless of size and orientation. In both cases, psychophysical data suggest that differences in visual size are resolved as differences in depth, such that transformation of size is done by translation in depth. Furthermore, the process of perceived or imagined translation appears to be stepwise additive such that a translation over a long distance consists of a sequence of smaller translations, the durations of these steps being additive. Both perceived and imagined rotation also appear to be stepwise additive, and combined transformations of size and orientation appear to be done by alternation of small steps of pure translation and small steps of pure rotation. The functional similarities suggest that common mechanisms underlie perception of apparent motion and purely mental transformations. In line with this suggestion, functional brain imaging has isolated neural structures in motion area MT used in mental transformation of size.     

EXPLAINING EMERGENCE: TOWARDS AN ONTOLOGY OF LEVELS

The vitalism/reductionism debate in the life sciences shows that the idea of emergence as something principally unexplainable will often be falsified by the development of science. Nevertheless, the concept of emergence keeps reappearing in various sciences, and cannot easily be dispensed with in an evolutionary world-view. We argue that what is needed is an ontological non reductionist theory of levels of reality which includes a concept of emergence, and which can support an evolutionary account of the origin of levels. Classical explication of emergence as “the creation of new properties” is discussed critically, and specific distinctions between various kinds of emergence is introduced for the purpose of developing an ontology of levels, framed in a materialistic and evolutionary perspective. A concept of the relation between levels as being inclusive is suggested, permitting the “local” existence of different ontologies. We identify, as a working hypothesis, four primary levels and explicate their nonhomomorphic interlevel relations. Explainability of emergence in relation to determinism and predictability is considered. Recent research in self-organizing non-linear dynamical systems represents a revival of the scientific study of emergence, and we argue that these recent developments can be seen as a step toward a final “devitalisation” of emergence.     

Visual processing speed in old age

Mental speed is a common concept in theories of cognitive aging, but it is difficult to get measures of the speed of a particular psychological process that are not confounded by the speed of other processes. We used Bundesen’s (1990) Theory of Visual Attention (TVA) to obtain specific estimates of processing speed in the visual system controlled for the influence of response latency and individual variations of the perception threshold. A total of 33 non‐demented old people (69–87 years) were tested for the ability to recognize briefly presented letters. Performance was analyzed by the TVA model. Visual processing speed decreased approximately linearly with age and was on average halved from 70 to 85 years. Less dramatic aging effects were found for the perception threshold and the visual apprehension span. In the visual domain, cognitive aging seems to be most clearly related to reductions in processing speed.