A dissertation submitted to the Faculty of Health Sciences, School of Therapeutic Sciences, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Science in Occupational Therapy. Johannesburg, 2017 / Occupational therapists routinely make use of the Test of Visual Perceptual Skills - Third Edition (TVPS-3), the Developmental Test of Visual Perception - Third Edition (DTVP-3) and the Developmental Test of Visual-Motor integration - Six Edition (Beery VMI-6) to determine visual perception and visual-motor integration (VMI) dysfunction. This study aimed to determine the validity and reliability of the TVPS-3, DTVP-3 and Beery VMI-6, on a sample of six to nine year old South African children. The scores for the typical children attending a mainstream school fell within the norms reported for children in the USA for all three tests. The DTVP-3, TVPS-3 and Beery VMI-6 were found to discriminate between children with and without a specific learning disability. All three assessments were found to have low levels of sensitivity, however were found to exhibit adequate levels of reliability. With the exception of the visual closure subtest on the TVPS-3 and DTVP-3, the tests cannot be used interchangeably but are all suitable for use with South African children from middle socio-economic backgrounds and can be used to identify visual perceptual and VMI dysfunction. This study was limited by a few factors such as that not all learners with a specific learning disability had visual perceptual problems, the participants used in this study only represented one region of Johannesburg and one province and lastly only learners aged six to nine years were included in this study. Further research on a more representative sample of South African learners is recommended as socio-economic status and environmental conditions have been shown to affect the performance on these tests. / MT2017

Chan Ka Ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 56-58). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.ii / Table of Content --- p.iv / Introduction --- p.1 / Experiment 1 --- p.15 / Experiment 2 and 3 --- p.22 / Experiment 2 --- p.25 / Experiment 3 --- p.32 / General Discussion --- p.37 / References --- p.56

Thesis (Ph.D.)--Boston University. / It is generally accepted that the brightness of a stimulus object is a factor in judgments of distance. However, very little knowledge about the functional relationships between photometric brightness and distance judgments have been obtained. Graham and others have shown that the psychophysical methods used to obtain stimulus-response relationships can also provide stimulus-stimulus functions. In the latter type of function information can be obtained which shows how one measurable stimulus attribute varies as a function of another, with the response as a parameter. This study was concerned with determining both of these relationships. The specific objectives in this study were: (1) to discover the functional relationships between ratios of photometric brightness and judgments of distance under binocular and monocular conditions (the major experiment) and (2) to show the effect of brightness ratios on judgments of distance when the absolute level of brightness is varied (the minor experiment). [TRUNCATED]

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Thesis (Ph.D.)--York University, 2008. Graduate Programme in Psychology. / Typescript. Includes bibliographical references. Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR39057

Thesis (Ph. D.)--Ohio State University, 1969. / Includes vita. Includes bibliographical references (leaves 71-77). Available online via OhioLINK's ETD Center.

Thesis (M.A.)--York University, 2001. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 95-103). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ66391.

There has long been a debate on which of the following two strategies we adopt while we are steering towards a stationary target: (1) The optic flow strategy, which suggests that we can find our ways towards our target by the alignment of our visually perceived heading, our instantaneous direction of locomotion, with the target. (2) The perceived direction strategy, in which we move towards a target by aligning our perceived straight ahead with the target. As we typically walk straight forward in our daily lives instead of making crab movements, our heading is usually well aligned with our perceived straight ahead while we are walking and it is difficult to tell which of the two strategies a person adopts when we observe him or her walking in naturalistic settings. There are multiple methods to displace the visual information about heading from our perceived straight ahead during walking, but inconsistent results have been obtained with these different methods – some showed that only the perceived direction strategy is used, while some found signs that both strategies are used simultaneously. Researchers supporting the perceived direction strategy suggested that the deviation of participants’ locomotive paths from that predicted by the perceived direction strategy observed in some experiments could be due to participants’ shifts in their perceived straight ahead driven by the displaced heading paradigm. So far, little work that addresses this concern have been conducted, thus, this thesis is intended to investigate this issue. In experiment I, participants were required to steer in virtual environments under displaced optic flow, with their steering performance as well as their shifts in perceived straight ahead at the end of each trial measured. A shift of the perceived straight ahead was observed, and its magnitude increased in conditions with richer optic flow. However, after taking this shift into account, participants still steered on paths intermediate between that predicted by the two different strategies. In experiment II, we have shown that a long period of steering under displaced heading can drive adaptations in our perceived straight ahead and corresponding changes in our steering behavior. From the results we conclude that optic flow has a profound effect on our perception of perceived straight ahead, and on top of that effect, optic flow also directly influences our guidance of steering towards a target. / published_or_final_version / Psychology / Master / Master of Philosophy