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S C Masin

Publications and source records attributed to S C Masin.

11 recordsLinked to original sources
PubMed1991

Attentional scanning and space errors.

Using the method of paired comparisons, pairs of simultaneous horizontal or vertical lines, with one line above and one below or one on the left and one on the right of a fixation point, respectively, were presented tachistoscopically for length comparison. Space errors were found to have a pattern similar to that of time errors. The tendency to guess the comparative response from the absolute magnitude of stimuli is proposed as a basis for time and space errors. Manipulation of attentional scanning, which implies a more frequent usage of this guessing strategy for one of the two lines in a pair, was shown to affect space errors.

Adult↗
PubMed1991

A weighted-average model of achromatic transparency.

A model of achromatic transparency based on the idea that neural representations of transparency are activated by proximal contours is described. It is proposed that the weighted average of the magnitudes of the representations of transparency relative to a perceived continuous transparent surface corresponds to the judgement of the overall degree of transparency of the same surface. Tests of this weighted-average model were carried out with bistable patterns formed by two overlapping surfaces that appeared opaque where they were superimposed on the background and transparent where they were superimposed on each other (partial transparency). In agreement with predictions from the weighted-average model, the rated degrees of transparency of these two surfaces were noncomplementary and independent of background reflectance. Two experiments confirmed the contention of this model that the relevant proximal contours for the judgement of partial transparency of the two overlapping transparent surfaces in a bistable pattern correspond to the part where these surfaces are superimposed.

Form Perception↗
PubMed1989

An explanation for the presentation-order effect in the method of constant stimuli.

The point of subjective equality obtained by the method of constant stimuli depends to a great extent on whether the standard (S) or the variable (V) stimulus occurs first. This presentation-order effect was studied using lines as stimuli. Successive S, V pairs were presented, with inter-stimulus and interpair intervals equal. Observers, who were not told which was S or V, reported whether a given line was longer or shorter than the immediately preceding line. Although the observers' subjective experience was of a train of lines that was not organized into pairs, the presentation-order effect still occurred. This implies that the effect does not depend on the order of presentation of the stimuli in an experienced pair. It was also shown that the observers could categorize line lengths, since they could identify stochastically the most frequent stimulus (S). We propose that the presentation-order effect depends on a decision process based on response probabilities inferred from length categories.

Attention↗
PubMed1988

Phenomenal thickness of a transparent surface.

Two basic phenomenal properties of an achromatic transparent surface have so far been reported in the literature, namely, density and lightness. This paper provides experimental support for a new phenomenal variable, the visual thickness of a transparent surface. The more transparent is a surface, the less thick it appears.

Depth Perception↗
PubMed1984

A psychophysical study of the Fuchs phenomenon.

The Fuchs phenomenon (ie the perception of transparency when the object seen through transparency lies on a homogeneous background, and does not jut out from under the transparent layer) has been studied by the numerical-rating method in two experiments, with the use of achromatic colours. The results of the first experiment show that the degree of transparency depends on the difference in colour between the object and the background. The results of the second experiment suggest that the processes producing the phenomenon are different in nature from the processes producing the kind of transparency most frequently studied in which the object juts out from under the transparent layer.

Color Perception↗