Thesis (M.Sc.)--York University, 2005. Graduate Programme in Kinesiology and Health Science. / Typescript. Includes bibliographical references (leaves 52-58). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url%5Fver=Z39.88-2004&res%5Fdat=xri:pqdiss &rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR11748

Thesis (Ph. D.)--University of Washington, 1987. / Vita. Bibliography: leaves [115]-121.

Thesis (M.A.)--Ohio State University, 1986. / Includes bibliographical references (leaves 38-40). Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--University of Oregon, 2006. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 118-124). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (Ph. D.)--Cornell University, 1920. / "Reprinted from the American journal of psychology, April 1920, vol. XXXI."

The key question of perception is how we manage to get an accurate, unambiguous and phenomenologically complete perception of the real world from proximal stimuli which are generally ambiguous and sometimes incomplete. Given a pattern as a visual input, we usually interpret it in one form although, in general, many interpretations of the pattern are possible. A study of the perceptual preference of partially occluded objects in two dimensional line drawings is presented. Two types of interpretations are considered, mosaic and completion. The interpretation is based on global as well as local simplicity. Global simplicity is measured by an information-load based on Leeuwenberg's model of coding theory and a minimum principle. The problems arising from this model are discussed and a solution based on an accessibility criterion is elaborated. However, this criterion alone does not solve the problem of local effect phenomena. Interpretations based on local cue information are then examined, and the issue of global versus local minima is considered from a computational perspective. In conclusion, a machine model of preference based on both local and global considerations is proposed, and its results compared to the results of psychological experiments on perceptual preference.

Thesis (Ph.D.)--Boston University. / Discrimination without awareness of the stimuli being responded to has been observed in a number of different experimental situations. In the classic case, the subject is instructed to relax or to engage in what is essentially a task of imagination, while incidental stimulation is presented at a level of intensity or duration such that he remains unaware of its presence. Responses of some comparatively unrestricted type are collected and analyzed for effects attributable to the stimulation. Present interest is in the case where the subject is effortfully attending to an objective task of discrimination. His range of possible responses to the task is quite narrow, and he is required to respond almost at once. The incidentally supplied stimulation is of a novel class, different from the stimulus material of the attended task; it is such as to present directly one of the possible task responses. The method used was an adaptation of a psychophysical judgment procedure, with individual subjects viewing the materials in a tachistoscope. A rectangular patch of standard size was presented first, followed in a few seconds by a test patch of variable size; the subject was required to report whether the latter was greater or smaller than the standard. A brief, unnoticed flash preceding the test patch carried the word greater or smaller or a nonsense control stimulus. A first experiment, using only three subjects, failed to yield any evidence of influence upon the judgments due to the unnoticed incidental words. In the second experiment, 32 subjects participated. The duration of the incidental flash waa gradually increased until the subject reported noticing its presence. Statistical analysis was restricted to the last 40 responses obtained at duration levels lower than the level at which recognition occurred. For the test patch of the same size as the standard (which had been presented on 24 of the 40 trials), it was clear that some subjects had indeed been influenced in the direction of agreeing with the unnoticed greater or smaller. The effect was statistically significant over all 32 subjects. About ten achieved a high degree of agreement with the incidental word, while the agreement scores of the others were distributed in approximately a chance fashion. Agreement was not influenced by sex of the subject. Four other test patches were of sizes greater or smaller than the standard. For two of these patches, subjects responded more accurately following the appropriate flash of greater or smaller than following the nonsense flash. No consistent relationships were found between latency of responding and agreement with the flashed stimulus. It is concluded from the main result that attended judgments of objective matters are (among some individuals) subject to influence from unreportable stimulation which directly presents the response to be used. This implies some necessary modification or extension of remarks made by Klein and others relative to this point. While attention usually acts to exclude activations which would be consciously rejected as inappropriate, such activations do (among some individuals) in a significant number of cases influence attended behavior without becoming conscious. A tentative conceptualization of the process is presented, based on psychoanalytic considerations by Kris and Fisher.

Visual crowding is a dramatic breakdown of object recognition that has been studied extensively as a gateway to determine the mechanisms that underlie normal object recognition. Despite numerous proposed models and mechanisms, a unifying account has yet to be found. Proposed mechanisms reach from purely hierarchical, bottom-up accounts that place crowding early in the processing stream, to high-level attention-based accounts that allow for recurrent processing and top-down feed-back. The aim of the current work was to investigate a range of factors that would help to differentiate between these accounts. Firstly, object-category was studied as a factor that would be expected to modulate crowding if the phenomenon were to affect object recognition during several stages along the processing stream. Secondly, knowledge was studied as a possible source of top-down feedback that, if found to have a direct influence on crowding, would provide evidence against a purely hierarchical account for object recognition. Thirdly, anticipation of flanker-presence was studied as a factor modulating volitional attention-allocation. Observing an influence of anticipation on object recognition under the influence of crowding, would provide support that crowding may be the result of a limitation to focus attention. Finally, object-familiarity was studied as another factor that may modulate crowding via top-down feedback. Of these factors, only object-familiarity was found to have an influence on visual crowding. However, instead of being the result of top-down feedback, hard-wired pathways developed based on repeated exposure might explain the effect of object-familiarity. In summary, none of the studied factors provided univocal evidence to suggest that crowding were to occur at multiple levels of object recognition, or that crowding were to be influenced by higher-level effects. Hence, it may be concluded that a purely hierarchical bottom-up account is sufficient to account for the effects visual crowding exerts on normal object recognition.

The aim of this research was to examine the social representation of the cyclone risk, identifying the organising principles of this social representation and to explore the place identifications of two communities in Madagascar who are affected by this risk. Furthermore, the study aimed to explore the relationship between the organising principles of the cyclone risk and the place identity principles of the inhabitants in these two communities and the effect that these have on managing the cyclone risk. A multiple method approach was adopted using both qualitative and quantitative methods. Issues of reliability, validity, gerneralisability and conducting psychological research in a non- western country are all discussed. Using the psychometric paradigm and interview data, the results showed that in both commiunities three main organising principles of the social representation of the cyclone risk were identified. These were blame for the cyclone occurrence, responsibility for dealing with the cyclone risk and personal threat due to the catastrophic potential of the cyclone risk. Regarding these organising principles the research showed that the salience of the elements within each organising principle increased during the cyclone season. There were also differences between the inhabitants of the two communities along the dimensions of the organising principles. The results also showed the inter-relationship that the organising principles of the social representation have with local place identity principles. It was also found that the organising principles of the social representation of the risk caused a threat to the four identity principles guiding identification with place among the inhabitants who live in the area with a greater vulnerability to the cyclone risk. The results highlight the need to contextualize risk perception research. They illustrate the utility of using a multi-method approach. The results also have implications for policy makers and aid workers who deal with the cyclone risk in Madagascar.

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