The study examined the relationship between reversals and several factors in 141 Grade 2 mainstream learners from average classes in Department of Education schools. The sample consisted of 77 female learners and 64 male learners. 55 of the 141 learners were older than 8 years and 131 of the 141 learners were right-handed.The study made use of correlational research where two or more variables are compared by measuring differences and looking for a relationship. Incorrect letter formation, gender and reversals in reading showed a statically significant difference between the group who had reversals compared to the group that did not have reversals in the class program that was used to identify learners with reversals. Furthermore the data collected only on the learners with reversals showed a mean scaled that was below average for position in space, figure ground and visual closure as well as for the motor-reduced quotient of the Developmental Test of Visual Perception -2. This group also displayed a high percentage of learners with difficulty with directionality as well as with crossing their midline. The results of the study were limited by the research design, as well as the lack of standardized tests available to test some aspects. Difficulty in gaining permission from parents to include learners in the study was also experienced which limited the final sample size. Further studies focussing on the treatment of the factors that showed a statistically significant relationship with reversals was recommended as well as placing more emphasis correct letter formation when teaching handwriting and publishing the results of this study in a journal accessible to educators and therapists was recommended. Copyright / Dissertation (MOccTher)--University of Pretoria, 2009. / Occupational Therapy / unrestricted

Reading and understanding algorithms is not an easy task and often neglected by educators in an introductory programming course. One proposed solution to this problem is the incorporation of a technological support tool to aid program comprehension in introductory programming. Many researchers advocate the identification of beacons and the use of chunking as support for code comprehension. Beacon recognition and chunking can also be used as support in the teaching model of introductory programming. Educators use a variety of different support tools to facilitate program comprehension in introductory programming. Review of a variety of support tools fails to deliver an existing tool to support a teaching model that incorporates chunking and the identification of beacons. The experimental support tool in this dissertation (BeReT) is primarily designed to encourage a student to correctly identify beacons within provided program extracts. BeReT can also be used to allow students to group together related statements and to learn about plans implemented in any semantically and syntactically correct algorithm uploaded by an instructor. While these requirements are evident in the design and implementation of BeReT, data is required to measure the effect BeReT has on the indepth comprehension of introductory programming algorithms. A between-groups experiment is described which compares the program comprehension of students that used BeReT to study various introductory algorithms, with students that relied solely on traditional lecturing materials. The use of an eye tracker was incorporated into the empirical study to visualise the results of controlled experiments. The results indicate that a technological support tool like BeReT can have a significantly positive effect on student comprehension of algorithms traditionally taught in introductory programming. This research provides educators with an alternative way for the incorporation of in-depth code comprehension skills in introductory programming.

A system has been implemented which is able to detect symmetrical groupings in edge images. The initial stages of the algorithm consist of edge detection, curve smoothing, and the extension of the perceptual grouping phase of the SCERPO [Low87] vision system to enable detection of instances of endpoint proximity and curvilinearity among curved segments. The symmetry detection stage begins by first locating points along object boundaries which are significant in terms of curvature. These key points are then tested against each other in order to detect locally symmetric pairs. An iterative grouping procedure is then applied which matches these pairs together using a more global definition of symmetry. The end result of this process is a set of pairs of key points along the boundary of an object which are bilaterally symmetric, along with the axis of symmetry for the object or sub-object. This paper describes the implementation of this system and presents several examples of the results obtained using real images. The output of the system is intended for use as indexing features in a model-based object recognition system, such as SCERPO, which requires as input a set of spatial correspondences between image features and model features. / Science, Faculty of / Computer Science, Department of / Graduate

According to the predictive coding approach to perception, the brain uses predictions based on previous experience to optimise perception, by allocating more computational resources to important or unexpected stimuli. Overall, predictions allow faster and more accurate recognition, but occasionally, when the prediction is incorrect, it may lead to a misperception. The aim of this thesis was to investigate the influence of top - down processes on perceptual decisions. I utilised misperceptions as a signature of those top - down influences and Signal Detection Theory to assess their size, type and direction. I used Electroencephalography to determine the stage of information processing at which different types of predictions influence sensory processing.The empirical studies are clustered around Topic 1: Influence of Predictions on Perception, Topic 2: Types of Predictions and Topic 3: Value as Modulator of Perception.Studies clustered in Topic 1 analysed and quantified the influence of predictions on perceptual decisions and showed that misperceptions can be triggered by wrong predictions only in very specific circumstances. In particular, misperceptions occurred only if there was some degree of correspondence between the wrong prediction and the sensory input. Otherwise, predictions were easily rejected, increasing the overall accuracy. I also demonstrated that misperceptions were most likely to happen in a window on the continuum of input quality where the stimulus - related uncertainty was highest. Topic 2 comprised experiments investigating different types of predictions and their interaction. Behavioural (but not EEG) results revealed interference between passive and active expectations. The early event related (ERP) components N1 and P2, as well as the P300, were all modulated by expectations. Expected events either increased or decreased the P300 amplitude, depending on whether the expected item was predictable and thus ignored, or awaited and thus flagged for further processing. This suggests that P300 might be an index of top - down resource allocation. Experiments within Topic 3 studied the influence of values, as examples of executive processes, on perceptual decisions, using either natural or acquired high - value stimuli. The results suggested that the process of recognition is adjusted in a top - down manner to account for the cost and benefit values related to different outcomes. The trade - off between processing time and accuracy is not fixed, but can be adjusted to optimise recognition in the task at hand. Furthermore, value can change the focus of perception, resulting in different elements of the sensory input being amplified or ignored. Overall, these results showed that misperceptions are 'intelligent mistakes' - a by - product of a top-down, prediction - based optimisation strategy that decreases the computational load, while increasing accuracy and improving the allocation of computational resources.

Contrast sensitivity to vertically oriented grating patterns with a sinusoidal luminance profile were examined between groups of observers varying either in gender or age. For each observer at each of the seven spatial frequencies tested (.75, 1.5, 3, 6, 7.5, 10, 15 cyc/deg) threshold values were calculated for either ascending or descending trials as well as a combination of both. These threshold values were numerically transformed into sensitivity values and contributed to a group mean contrast sensitivity score for each spatial frequency. No significant effect of gender was found but younger observers (mean age=22.6 yrs.) exhibited significantly better contrast sensitivity than the older aged group (mean age=66.2 yrs.) for ascending trials at 3, 1.5 and .75 cyc/deg--the lowest spatial frequencies tested. Contrast sensitivity was also correlated with various measures. These findings were discussed in relation to the existing literature on age and spatial contrast sensitivity and since the machine used to examine the contrast sensitivity function (CSF) in this study utilized a laser interferometric method of stimulus generation, possible neurological changes with aging to explain this noted loss were also considered. Also discussed were various parameters that effect the CSF with a view toward explaining the disparate findings of various existing studies of age and the CSF. / Arts, Faculty of / Psychology, Department of / Graduate

The ecological movement in the psychology of perception, founded by James J. Gibson, hold that traditional approaches to perception are based upon certain fundamental mistakes. The chief one, ecological theorists claim, is that perceptual information pickup consists of the application of certain cognitive processes to sensory input which is not specific to features of organisms' environment. Gibson's fundamental claim is that perception does not require the processing of some form of sensory input. In this sense, the ecological approach is said to be a theory of direct perception. An important debate over the Gibsonian view concerns the question of whether or not perceptual information pickup without cognitive processing is a coherent notion. Among the more recent writers who claim that the ecological view will not work as it stands are Jerry A. Fodor and Zenon W. Pylyshyn. They claim, essentially, that Gibson's approach has no means for accounting for intentionality. Fodor and Pylyshyn are answered by four prominent Gibsonians who claim such criticisms are utterly baseless. These ecological theorists, Michael Turvey, Robert Shaw, Edward Reed, and William Mace endeavour to show how their approach can indeed account for intentionality. This debate between Fodor and Pylyshyn on the one hand, and Turvey, Shaw, Reed, arid Mace on the other is a perfect example of the kinds of misunderstandings that have arisen between Gibsonians and proponents of traditional view. In this thesis, I supply a detailed description of Gibson's model as it relates to the issue of how intentionality could survive perception without processing. Fodor and Pylyshyn's understanding and assessment of the Gibsonian position will then be examined. Although these defenders of traditional views have, some important concerns,.they also seem not to have a proper grasp of some Gibsonian concepts. In particular, Fodor arid Pylyshyn have an unsatisfactory grasp of the notion of an invariant. There are more serious misunderstandings evident in the response to Fodor arid Pylyshyn given by Turvey et al. I point out that these ecological theorists have difficulties with philosophical terms and theories they employ in defense of Gibson. As a result of evident confusions over notions of intension, extension, and property, arid confusions over the nature of Fred I. Dretske's theory of natural laws and Hillary Putnam's theory of natural kinds, Turvey et al do not manage to show how Gibson's approach could account for intensionality. I conclude by suggesting that the ecological approach nevertheless is compatible with the idea, of analyzing perceptual information pickup in terms of behaviour, or dispositions to behave. On such an interpretation, the ecological approach is similar in many important respects to the D.M. Armstrong's philosophical theory of perception. The comparison provides ecological theorists with a precedent as well as philosophical model to consult in order to better, understand the philosophical language and terminology. On the other hand, the comparison with Armstrong provides philosophers of perception with a means for approaching Gibson's view and the problems with which it will he confronted. / Arts, Faculty of / Philosophy, Department of / Graduate

The present work is an examination of the mechanisms underlying temporal processing in vision. Recent studies have shown that when observers are asked to identify two objects presented in rapid succession, identification of the first object is quite accurate, while identification of the second object is poor when it folows the first at very brief inter-target intervals (i.e. 200-500 ms). This second-target deficit is known as the attentional blink. According to bottleneck models, the attentional blink occurs because processing of the first target prevents the second target from gaining access to high-level processing. A strong prediction of this account is that if processing time for the first target is increased, the magnitude of the attentional blink should also increase. This prediction is confirmed in experiments. It is argued that these results strongly support bottleneck models as an account of the attentional blink in particular and of temporal processing more generally. / Arts, Faculty of / Psychology, Department of / Graduate

Submitted by Haroudo Xavier Filho (haroudo.xavierfo@ufpe.br) on 2016-04-19T14:22:21Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) SUMARIO NOVO_Dissertação_final_Juliana_Barros.pdf: 2081494 bytes, checksum: 5369e10ca48228172d4af19c12f46e6c (MD5) / Made available in DSpace on 2016-04-19T14:22:21Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) SUMARIO NOVO_Dissertação_final_Juliana_Barros.pdf: 2081494 bytes, checksum: 5369e10ca48228172d4af19c12f46e6c (MD5) Previous issue date: 2015-07-10 / FACEPE / Estudos recentes mostram que pessoas com esquizofrenia apresentam alterações em vários domínios cognitivos, incluindo a percepção da forma. O presente estudo tem como objetivo descrever o processo de construção e validação de conteúdo e de face do Teste de Organização Perceptual Visual (TOPV), que consiste num instrumento neuropsicológico que visa testar a percepção visual de forma em esquizofrênicos. Um grupo de 7 juízes, peritos em Neurociências e Percepção Visual foi solicitado a avaliar um conjunto de 50 imagens de borrões de tinta com simetria vertical. A tarefa consistiu em contornar todas as figuras percebidas e julgar as imagens quanto à qualidade e pertinência para o teste, com pontuação distribuída em escala Likert. O Índice de Validade de Conteúdo (IVC) das pranchas foi calculado e 23 imagens apresentaram IVC ≥ 0,85 em ambos os critérios, sendo que apenas 13 obtiveram concordância quanto ao número de imagens e 3 imagens foram excluídas por sugestão dos juízes, por apresentarem baixa neutralidade. Como resultado foram selecionadas para compor o protocolo clínico final do TOPV 10 imagens, sendo 2 policromáticas, 3 em escala de cinza e 5 em escala de cinza e vermelho. / Recent studies show that people with schizophrenia have changes in several cognitive domains; include perception of shape. This work aims to describe the process of construction and validation of content of Perceptual Organization Visual Test (TOPV), which is an neuropsychological instrument to assess visual perception of form in schizophrenics. A group of 7 judges, experts in Neuroscience and Visual Perception was asked to evaluate a set of 50 images of ink blots with vertical symmetry. The task consisted to circumvent any perceived images and judge the quality of the image and relevance to the test, with scores distributed in Likert scale. The Content Validity Index (IVC) of the boards was calculated and 23 images had IVC ≥ 0.85 in both criteria, only 13 had agreement on the number of images and 3 images were excluded for convenience. The clinical protocol of TOPV included 10 images, 2 polychromatic, 3 grayscale and 5 grayscale and red.

An ongoing debate is whether people with autism spectrum disorder (ASD) have a local processing bias and to what extent impaired contextual processing is associated with this bias. The set of experiments employed in this project examined global and local processing, shifts between global and local processing, and low- and high-level visual processing in an attempt to address this issue. This thesis tested the hypotheses that (1) a local processing bias is associated with impaired global processing in ASD individuals, and (2) atypical processing style is linked with ASD severity. Twenty ASD individuals and 20 IQ and age (15-30 years) matched normal controls were administered a novel embedded figures task (local processing advantageous), a novel form matching task and novel shape integration task (global processing advantageous), a local-global switching task (which assessed attention broadening and attention narrowing ability), and a local and global motion detection task. The Social Responsiveness Scale was used to assess ASD severity. The ASD group correctly detected significantly more embedded shapes than controls. Compared to controls, ASD participants were disproportionately slower on the shape integration task relative to the form perception task. No overall group differences were found in attention broadening or attention narrowing ability. In addition, no group differences were found in local or global motion perception. Results also revealed a significant correlation between ASD severity and (1) faster response time on the embedded figures test, (2) slower response time on the shape integration task, (3) reduced attention broadening ability, and (4) reduced global motion perception. These findings confirm previous reports of enhanced local visual processing in ASD, and suggest that while global form perception is intact in ASD, global integration is more problematic. There was no evidence of generalized attentional impairments or motion perception abnormalities in ASD participants, suggesting that lower-level perceptual functions may be spared in people with ASD. Perhaps most intriguing was the observed association between ASD severity and enhanced local perception and impaired global processing. This association suggests that both a local processing bias and impaired global processing may play a role in the behavioral aspects of ASD symptomatology.

The goal of this thesis was to present a teaching method which would demonstrate increased visual awareness in general education college students. The particular approach presented for that purpose was also designed to be of potential benefit to students' total educational experience. To that end sane conditions and specific research were introduced as necessary considerations for the teaching approach and for the role of art education as it pertains to the thesis goal.