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Memory for visual patterns was examined in 131 patients with unilateral temporal- or frontal-lobe excisions and 32 normal control subjects. A deficit in short-term memory for matrices of increasing complexity was exhibited by the right frontal-lobe group. Right temporal lobectomy impaired cued recall of visually homogeneous matrices at each of four serial positions. On the delayed recognition of complex visual scenes, right temporal lobectomy decreased identification of changes in figurative detail and spatial composition, whereas right hippocampectomy impaired identification of changes in spatial location. The interplay between verbal and pictorial codes in memory was also investigated using related word-design pairs. Right or left temporal lobectomy affected the number of designs recalled but only the right temporal-lobe group produced designs of poor quality. When cued with the words, the left temporal-lobe group produced fewer designs than the control subjects, demonstrating a reduced ability to retrieve pictorial information through verbal labels.

The purpose of this study was to develop a valid and reliable measure of ability to render pictorial depth. The instrument, which was named the Pictorial Depth Rendering Test, is hereafter referred to as the PDRT.The instrument is a drawing completion test containing twenty-one pictures. Each picture is a simplified line drawing of one or more familiar objects located in pictorial space through the use of monocular depth cues. Written instructions that appear with each of the drawings ask for additional visual information to be added to the pictures. The twenty-one pictures contain a total of thirty-six scoring items providing a total possible score of thirty-six. A written set of scoring instructions was also developed for the instrument.In a pilot study the test was administered to a convenience sample of sixty subjects with an age range of seven through twenty-five. The sample was divided into six groups: lower elementary; upper elementary; junior high; senior high; college non-art students, and college art majors. To determine concurrent validity of the instrument, subjects were administered two other perceptual tests: MacGregor's Perceptual Index, and Silhan's SpatialIllusionism Sensitivity Test. Significant correlations were obtained between scores on all three tests, and scores on the PDRT were also found to correlate highly with age and grade. A high correlation of .99 was found between two sets of PDRT test scores obtained from two independent test scorers. An item discrimination index was computed on the pilot study data and four items were found to be moderate, low, or non-discriminators. The pictures containing the four items were subsequently redesigned.In the main study, the refined version of the PDRT and the Spatial Illusionism Sensitivity Test were administered to a sample of 309 elementary, secondary, and college students divided into six groups: first and second grade; fourth and fifth grade; junior high school; senior high school; college non-art, and college art majors. The perceptual Index was administered to a random sample of sixty subjects were composed of ten randomly selected students from each of the six groups. A .90 correlation was obtained between scores on correlation was obtained between scores on the PDRT and scores on the Spatial Illusionism Sensitivity Test. Significant correlations were also found between scores on the PDRT and the age and grade variables. No significant relationship was obtained between the sex variable and scores on the PDRT, although group mean scores indicated that male subjects tended to score more highly than female subjects on all three tests.The main study data were subjected to one way analysis of variance and the F-ratio obtained indicated that significant differences exist among group mean scores on the PDRT. A linear progression of PDRT group mean scores was also noted.A second item discrimination index was computed on the PDRT scores of the random sample of sixty subjects drawn from the main study sample. The D-values obtained from the second item analysis revealed that the refined version of the test contains thirty-five high discriminating items and one moderate discriminating item.A Kuder Richardson (KR-20) correlation coefficient of .90 which was obtained for the total main study PDRT data indicated that the instrument has a high level of internal reliability. Subsequent KR-20 correlations which were computed for each of the six groups revealed that the test does not have a high level of reliability when administered to lower elementary students.From the results of the study, the researcher concluded that the refined version of the PDRT contains sufficiently high levels of validity and reliability to permit its use as a measure of ability to render pictorial depth when administered to fourth grade or above.

The purpose of the study was to compare the perceptions of subordinates with top managements? own perceptions regarding top management leadership and innovative ability and to determine whether differences and/or similarities exist. The Multi Leadership Questionnaire (MLQ form 5X) from Avolio & Bass (2004) was used to measure self– and subordinates? perceptions of leadership styles. The Situation Outlook Questionnaire (SOQ) was used to measure leaders? self– and subordinates? perception on the ability to be innovative. The questionnaires were completed by 6 executive committee members (top management) and 94 subordinates that have a direct relationship with the executive committee members in an agricultural business. The research findings revealed that there is a significant difference between leaders? (executive committee members) self–perceptions on their own leadership and ability to be innovative, versus the perceptions of their subordinates on their leadership and ability to be innovative. The research showed that leaders tend to assess themselves higher than their subordinates do. Both leaders and subordinates indicated that the leaders have a transformational leadership style. The results also showed that there is a weak to moderate, positively significant correlation between innovation and transformational leadership styles. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2012.

The purpose of the study was to compare the perceptions of subordinates with top managements? own perceptions regarding top management leadership and innovative ability and to determine whether differences and/or similarities exist. The Multi Leadership Questionnaire (MLQ form 5X) from Avolio & Bass (2004) was used to measure self– and subordinates? perceptions of leadership styles. The Situation Outlook Questionnaire (SOQ) was used to measure leaders? self– and subordinates? perception on the ability to be innovative. The questionnaires were completed by 6 executive committee members (top management) and 94 subordinates that have a direct relationship with the executive committee members in an agricultural business. The research findings revealed that there is a significant difference between leaders? (executive committee members) self–perceptions on their own leadership and ability to be innovative, versus the perceptions of their subordinates on their leadership and ability to be innovative. The research showed that leaders tend to assess themselves higher than their subordinates do. Both leaders and subordinates indicated that the leaders have a transformational leadership style. The results also showed that there is a weak to moderate, positively significant correlation between innovation and transformational leadership styles. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2012.

Experiments were conducted examining human interception of projectiles. It was found that fielders tend not maintain a linear optic trajectory (LOT) as advocated by McBeath, Shaffer, and Kaiser (1995) for interception in two-dimensions. Furthermore, it was shown that its curvature provided an ambiguous cue to action. New interception models were proposed based on optic acceleration cancellation (OAC) and the constant δ model significantly improved upon the performance of the LOT model. Awareness of interception strategy was investigated by questioning subjects about their angle of gaze variation during the ball flight. A lack of awareness of the critical information that guides interceptive behaviour was demonstrated. It is proposed that the information is stored implicitly, challenging the position of Shanks and St. John (1994). Subjects were asked to discriminate the visual information that they experienced before running to catch real balls to examine the validity of experiments that test human ability to discriminate the acceleration of simulated trajectories. Discriminative performance found to remain high even when the duration of viewed information is reduced. This intact discriminative ability led to the suggestion that trajectory discrimination occurs very rapidly after ball launch. The movement and gaze angle of fielders running to catch under conditions in which OAC cannot be sustained was analysed. Subjects showed little deviation from the strategy until the final moments of the catch. The overall conclusion to the thesis is that subjects react rapidly to the optic acceleration of a projectile to determine interceptive behaviour but may not be aware of the sensory basis of their decision and use an approximate version of the constant δ strategy to reach the interception point.

The present thesis reports psychophysical and modeling studies on the spatial properties of visual mechanisms mediating the perception of mirror symmetry in human vision. In a first set of experiments, patterns were filtered for power spectra that decayed with spatial frequency according to variable slopes. Results revealed that symmetry detection is optimal if contrast energy is roughly equated across log-frequency bands (i.e. 1/f2) and that, under such conditions, spatial scales contribute equally and independently to symmetry perception. In a second study, random-noise patterns were filtered for various orientation bands. Results showed that symmetry perception is possible at all orientations, is mediated by oriented mechanisms, and is computed independently in different orientation channels. Data also revealed that the dimensions of the spatial integration region (IR) for symmetry vary with orientation in a way that approximately matches the spatial distribution of information in the stimulus. Finally, symmetry detection was measured for bandpass textures of variable spatial density and variable contrast polarity. For such patterns, it was found that symmetry is computed at a spatial scale proportional to stimulus density and that mechanisms insensitive to contrast polarity (i.e. second-order) are involved in the scale-selection process. / Overall, results from empirical and modeling work revealed an intimate link between symmetry perception and the properties of spatial filters. In particular, I argue that the size of the IR tends to vary such that a fixed amount of information is integrated irrespective of the spatial properties of the stimulus. Implications for the functional architecture of symmetry perception are discussed, and a paradigm for future research in symmetry perception is proposed in which spatial filtering is extended to higher orders of spatial complexity.

Thesis (M.A.)--York University, 2006. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 89-93). 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:MR19699

Thesis (M.S.)--University of British Columbia, 2006. / Includes bibliographical references (leaves 45-48).