Biomedical subjects
Publications and source records attributed to L Zusne.
A conceptual model that relates all forms of multistable figures is presented. It has the form of a tetrahedron whose faces and edges represent the variables of information contained in the ground, in the figure-ground relationship, in the extent of organization of the ground, and meaningfulness.
Although Purkinje observed the eponymous phenomenon at dawn, it is identical to what happens in the dark-adapting eye. It is shown that most modern definitions of the phenomenon couch it in terms of dark adaptation and that the author's definition of it in similar terms is justified in spite of Brozek's objection.
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The count of publications on geometric-optical illusions and the bibliography of extant books on the topic are brought up to date. The number of publications now exceeds 1100 and the number of books is 35.
A replication of Descartes' demonstration of the inversion of the retinal image is described. Suggestions are made for both preparing a cattle eye and constructing an artificial one for purposes of classroom demonstration.
Confirmation was obtained that the phenomena of figure obscured by random noise and embedded figures form a triangular, planar continuum. 80 preschoolers, third- and sixth-graders, and college students searched for and recognized a nonrepresentational figure obscured to different degrees by noise that varied form random and unrelated to the contours of the figure to highly embedding contexts. Response time varied directly with the amount of noise and with embeddedness, and inversely with age, producing analogous response planes along the age dimension.
72 random polygons and their curvilinear transformations were exposed for 3 sec. to 40 subjects who produced written associations during a 10-sec. interval. The number of associations varied, in general, directly with the amount of curved contour as well as with the degree of contour dispersion. The amount of variance accounted for by these two variables was small, however. Differences in curvature produced much greater differences in the content of the associations, greater degrees of curvature evoking more associations that were curved, man-made objects or living things and fewer associations that were straight-edged, man-made objects. A significant and inverse relationship was also established between contour dispersion and associations that were non-living, natural objects. It is concluded that physical form dimensions, especially curvature, affect less the association value (connotative meaning) of visual forms and much more their denotative meaning.
In 4 experiments, in which 66 subjects participated, the perception of 6 types of curved contours in two-dimensional shapes was studied. Random polygons and their curvilinear transformations were presented for detection under low-luminance contrast conditions, oddity-type discrimination problem solving, tachistoscopic identification, and identification involving visual acuity in distance vision. In all experiments curvature affected perception at statistically significant levels, but the extent of this effect was a function of (1) the locus and direction of curvature, (2) the level of compactness-jaggedness of the figure, and (3) the nature of perceptual task. Shapes with acute corners were more easily perceived than shapes with curved corners. Within these two classes of shapes, those with convex sides were perceived as having greater curvedness than those with concave contours. However, the degree to which curvature affected response was determined primarily by the nature of the perceptual task.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.