Analysis of simple reaction time to a sinusoidal grating by means of a linear filter model of the detection process

Simple reaction time (RT) to a sinusoidal grating was analyzed in terms of a linear filter model of the detection process. First, RT contrast functions were determined over a wide range of spatial frequencies and retinal illuminances. Second, calculating the time course of the linear filter's response, theoretical visual latency contrast functions were derived for the same conditions of spatial frequency and retinal illuminance as those in the RT measurements. Comparison of the two functions showed that the contrast dependence of the RT functions was much larger than that of the visual latency functions. The discrepancy between the two functions was satisfactorily described as a power function of the slope of the filter's response at threshold level. On the basis of these results, we propose a model of the RT process. According to the model, the RT process is mediated by a cascade that consists of a level detector, which includes a linear filter followed by a threshold device, and a differentiator of the filter's response.     

Analysis of simple reaction time to sinusoidal grating by means of a linear filter model of the detection process

Attention, Perception, & Psychophysics - Simple reaction time (RT) to a sinusoidal grating was analyzed in terms of a linear filter model of the detection process. First, RT contrast functions...     

Correlations of conceptual development with motor skills for a Turkish sample of kindergarten children

The purpose was to research the conceptual development and motor skills of 36 healthy children of kindergarten age (M age = 67.6 mo., SD = 3.6). 19 girls and 17 boys completed the Bracken Basic Concept Scale-Revised and the Bruininks-Oseretsky Test of Motor Proficiency-Short Form.     

Relationship between upper extremity kinesthetic sense and writing performance by students with low vision

Kinesthetic sense plays an important role in writing. Children with low vision lack sensory input from the environment given their loss of vision. This study assessed the effect of upper extremity kinesthetic sense on writing function in two groups, one of students with low vision (9 girls and 11 boys, 9.4 +/- 1.9 yr. of age) and one of sighted students (10 girls and 10 boys, 10.1 +/- 1.3 yr. of age). All participants were given the Kinesthesia Test and Jebsen Hand Function Test-Writing subtest. Students with low vision scored lower on kinesthetic perception and writing performance than sighted peers. The correlation between scores for writing performance and upper extremity kinesthetic sense in the two groups was significant (r = -.34). The probability of deficiencies in kinesthetic information in students with low vision must be remembered.     

Incredible Worlds, Credible Results

Robert Sugden argues that robustness analysis cannot play an epistemic role in grounding model-world relationships because the procedure is only a matter of comparing models with each other. We posit that this argument is based on a view of models as being surrogate systems in too literal a sense. In contrast, the epistemic importance of robustness analysis is easy to explicate if modelling is viewed as extended cognition, as inference from assumptions to conclusions. Robustness analysis is about assessing the reliability of our extended inferences, and when our confidence in these inferences changes, so does our confidence in the results. Furthermore, we argue that Sugden’s inductive account relies tacitly on robustness considerations.

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Bottom-up clues in target finding: why a Dalmatian may be mistaken for an elephant

We provide informal psychophysical support for a strategy where bottom-up features guide attention toward a target, and the top-down path interprets hypothetical shapes at the target location--as opposed to a dominant top-down approach. In our survey, for which we used the familiar picture of a Dalmatian dog against a dappled background, (i) 75% of subjects initially found a bulging body which overlaps that of the dog, but final 'top-down' percepts were unexpected: nearly all subjects assigned an incorrect head and limbs to the body; (ii) after random rotation of texture elements overlapping computed features only 45% of subjects reported a bulging body, with a few adding limbs etc. The picture of the Dalmatian dog must therefore contain many bottom-up features--a top-down strategy may find 'incorrect' targets at correct target locations. Computational support for these claims is more easily constructed than one may expect. We could compute at least two bottom-up features, both useful in 3-D surface interpolation from 2-D scenes, which yielded significant values at the location of the Dalmatian dog: anisotropic texture compression and affine texture distortion cues. We therefore conclude that the role of top-down processing is overstated in a traditional example such as the Dalmatian dog picture.