Thesis (Ph. D.)--Ohio University, March, 2000. / Title from PDF t.p.

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Typescript (photocopy). / Digitized by Kansas Correctional Industries

published_or_final_version / abstract / Psychology / Master / Master of Philosophy

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaves 225-237. / by William Eric Leifur Grimson. / Ph.D.

The processes underlying the perceptual analysis of visual form are believed to have minimal interaction with those subserving the perception of visual motion (Livingstone and Hubel, 1987; Victor and Conte, 1990). Recent reports of functionally and anatomically segregated parallel streams in the primate visual cortex seem to support this hypothesis (Ungerlieder and Mishkin, 1982; VanEssen and Maunsell, 1983; Shipp and Zeki, 1985; Zeki and Shipp, 1988; De Yoe et al., 1994). Here we present perceptual evidence that is at odds with this view and instead suggests strong symmetric interactions between the form and motion processes. In one direction, we show that the introduction of specific static figural elements, say 'F', in a simple motion sequence biases an observer to perceive a particular motion field, say 'M'. In the reverse direction, the imposition of the same motion field 'M' on the original sequence leads the observer to perceive illusory static figural elements 'F'. A specific implication of these findings concerns the possible existence of (what we call) motion end-stopped units in the primate visual system. Such units might constitute part of a mechanism for signalling subjective occluding contours based on motion-field discontinuities.

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Pattern vision in the rat bas been most effectively studied by a jumping method devised by Lashley (1930). This procedure requires the rat to jump at one of two cards bearing the patterns to be discriminated. On the basis of Laehley’s extensive anatomical and behavioural studies it has been assumed that the cards fall within the rat’s binocular field of vision and, consequently, that they are seen as a whole at the time when the visual patterns begin to influence behaviour during discrimination learning. Ehrenfreund (1948), however, thought that the rat’s effective field, in the Lashley jumping apparatus, might be limited to the lower margin of the cards, and has demonstrated this experimentally in certain conditions of training. Since Ehrenfreund’s data have been interpreted as bearing on the current continuity-noncontinuity controversy concerning the nature of learning, his experiment is of general importance. Ehrenfreund trained his rats on a modified Lashley jumping apparatus to discriminate between an upright and an inverted triangle in two differing experimental situations. In one condition, the triangles were raised eight centimetres above the bottom margin of the cards. The platform from which the rats jumped, as in the usual procedure, remained level with the platform on which they found food. In the second, the platform was also raised, so that the rats were jumping at the centre of the cards where the triangles were now located. [...]

Thesis (Ed. D.)--Illinois State University, 1982. / Title from title page screen, viewed April 13, 2005. Dissertation Committee: Max Rennels (chair), Macon Williams, Gordon Redding, Heather Hanlon, Richard Hentz, Robert Stefl. Includes bibliographical references (leaf 27) and abstract. Also available in print.