This researched aimed to explore the effects of the Human Immunodeficiency Virus (HIV) upon the visuospatial abilities of HIV-positive adolescents on antiretroviral treatment in South Africa. The literature suggests that the neurology responsible for visuospatial abilities (specifically various white-matter tracts in the brain) is very susceptible to the damaging effect that HIV has on the brain. The research sample consisted of vertically transmitted HIV-positive adolescents, on first line antiretroviral treatment, with a HIV-negative control group comparable on age and SES. The results indicated that there is a significant difference in the visuospatial abilities between adolescents with and without HIV. The expressions of these deficits were displayed differently between males and females, highlighting a differing developmental neurology, and the effect of HIV upon it. The viral strength and health of the immune system were also examined as variables and illuminated interesting results. Overall, the research illustrates the negative effect that HIV has upon developing neurology and the subsequent effects on visuospatial abilities.

<p> </p><p>Den socialt kompetente har hög social status, många vänner, ett funktionellt beteende och sociala förmågor så som empati och hjälpsamhet. Avsaknad av social kompetens innebär bland annat känslomässiga och beteendemässiga problem. I denna studie medverkade totalt 30 gymnasieelever som genomgick två arbetsminnestest samt fyllde i en självvärderingsenkät som mäter social kompetens. Syftet var att undersöka om det finns ett samband mellan en tonårings arbetsminne och sociala kompetens. Studien begränsades till att mäta arbetsminnets fonologiska och visuellspatiala lagringsenheter samt två sociala förmågor; prosocialt beteende och initiativtagande. Inga signifikanta korrelationer mellan arbetsminne och social kompetens kunde påvisas. Eventuellt kan de icke existerande korrelationerna bero på att fel del av arbetsminnet eller fel del av den social kompetens stod i fokus för studien.</p>

Den socialt kompetente har hög social status, många vänner, ett funktionellt beteende och sociala förmågor så som empati och hjälpsamhet. Avsaknad av social kompetens innebär bland annat känslomässiga och beteendemässiga problem. I denna studie medverkade totalt 30 gymnasieelever som genomgick två arbetsminnestest samt fyllde i en självvärderingsenkät som mäter social kompetens. Syftet var att undersöka om det finns ett samband mellan en tonårings arbetsminne och sociala kompetens. Studien begränsades till att mäta arbetsminnets fonologiska och visuellspatiala lagringsenheter samt två sociala förmågor; prosocialt beteende och initiativtagande. Inga signifikanta korrelationer mellan arbetsminne och social kompetens kunde påvisas. Eventuellt kan de icke existerande korrelationerna bero på att fel del av arbetsminnet eller fel del av den social kompetens stod i fokus för studien.

It has been shown that there exists a relationship between levels of metacognitive ability and estimation of personal ability for largely verbally-based tasks, where those with lessened facility for the task tend toward overestimation of their aptitude relative to their peers (Kruger and Dunning, 1999). This study examines this effect for a task of mechanical ability for volunteer participants (n = 69), where participants were given an abbreviated form of the Bennett Mechanical Comprehension Test (BMCT) to establish a level of competency. Following the administration of the BMCT, the participants were then asked to speculate on the hypothetical grade for their performance, as well as the relationship between their hypothetical grade, and the grades of others. Participants then "tutored" a hypothetical student on the solution to one of the problems found on the BMCT, and their explanations were coded for degree of bias towards confirmation versus disconfirmation that was utilized in the problem solving. It was found that females' basic ability had a greater range than males', and females on the high and low ends of competency made greater use of confirming strategies in their problem solving. This is indicative of the overall observed interaction effect between Gender, Perceived Relative Competence, and Actual Competence observed in this study.

Patients with amnestic type of mild cognitive impairment (aMCI) are diagnosed mainly on the basis of performance in verbal memory tests. This thesis deals with the use of a nonverbal test called the Brief Visuospatial Memory Test-Revised (BVMT-R) for the diagnosis of mild cognitive impairment (MCI). This research compared the performance of patients with clinical diagnosis of MCI (N=79) using the BVMT-R with the performance of these patients using the Auditory Verbal Learning Test (AVLT), the AVLT being a validated instrument for differentiating aMCI patients from healthy control patients. Both tests follow a similar design paradigm, but they differ in the type of stimuli measured: the BVMT-R tests memory for nonverbal material and the AVLT tests for verbal material. Results showed that there is a moderate correlation between scores (total score, delayed recall score) of the BVMT-R and equivalent scores of the AVLT. Further analyses of performance of MCI patients in both tests (in total scores and delayed recall scores) identified that there was a proportion of patients tested using the BVMT-R with memory impairment that did not show any memory impairment using the AVLT. Our findings indicate a favorable diagnostic potential of BVMT-R in the diagnostics of mild cognitive impairment. Keywords:...

<p>The aim of the present thesis was to study sex differences in memory and other cognitive bilities in healthy adults. In Study I, participants performed a number of episodic memory tasks that were more or less verbal in nature. Results showed that women performed on a higher level than did men in the episodic memory tasks where it was possible to use verbal labels, whereas men performed on a higher level than did women in a visuospatial episodic memory task. In Study II, women’s advantage in face recognition was investigated.Results showed that women performed at a higher level than did men only in the recognition of other women’s faces. In Study III, sex differences in cognitive tasks as well as brain measures were investigated in healthy older adults. Results showed that only the sex differences in a motor task could, to some extent, be explained by sex differences in one of the brain measures. The findings, as well as possible explanations for these patterns of results, are discussed in a theoretical context.</p>

Em estudos sobre a atenção visuoespacial automática, as regiões de aparecimento dos estímulos são comumente demarcadas na tela. Resultados preliminares de nosso laboratório demonstraram que as demarcações favorecem a manifestação do efeito atencional. O presente estudo estendeu esse achado determinando o modo de atuação destes estímulos. Em um primeiro experimento, confirmamos o achado de que o efeito atencional observado quando as demarcações estão presentes diminui na ausência delas. Em um segundo experimento, investigamos a possibilidade do efeito atencional não se manifestar na ausência das demarcações devido a um desvio muito precoce do foco atencional do local inicialmente atendido, porém o efeito atencional não se manifestou na ausência das demarcações quando se estabilizou o foco atencional por um período maior no local atendido. No terceiro experimento, identificamos a possibilidade do efeito atencional não se manifestar na ausência das demarcações devido a um mascaramento anterógrado de determinado estímulo alvo pelo estímulo precedente mobilizador da atenção / In studies about automatic visuospatial attention, the appearance of the stimulus regions are commonly marked on the screen. Preliminary results from our laboratory demonstrated that the placeholders favors the development of attentional effect. This study extended this finding by determining the mode of action of these stimuli. In a first experiment, we confirmed the finding that the attencional effect observed when placeholders decreases in their absence. In a second experiment, we investigated the possibility of attentional effect do not manifest in the absence of placeholders due to a very early turning from the attentional focus of initially attended site, however, the attentional effect did not manifest in the absence of placeholders when it stabilized the attentional focus by a longer period in the treated site. In the third experiment, we identified the possibility of the attentional effect do not manifest in the absence of placeholders due to an anterograde masking of certain stimulus target by mobilizing previous stimulus of attention

The aim of the present thesis was to study sex differences in memory and other cognitive bilities in healthy adults. In Study I, participants performed a number of episodic memory tasks that were more or less verbal in nature. Results showed that women performed on a higher level than did men in the episodic memory tasks where it was possible to use verbal labels, whereas men performed on a higher level than did women in a visuospatial episodic memory task. In Study II, women’s advantage in face recognition was investigated.Results showed that women performed at a higher level than did men only in the recognition of other women’s faces. In Study III, sex differences in cognitive tasks as well as brain measures were investigated in healthy older adults. Results showed that only the sex differences in a motor task could, to some extent, be explained by sex differences in one of the brain measures. The findings, as well as possible explanations for these patterns of results, are discussed in a theoretical context.

The efficiency of human visual information processing is supported by numerous attentional resources. These resources ensure that behaviourally relevant information within visual scenes is selected for detailed processing, while behaviourally irrelevant information is ignored. One of these attentional resources—reflexive visuospatial attention—operates by prioritising locations in visual space in response to the appearance of salient stimuli. The purpose of the present dissertation was to examine how this type of attention contributes to the efficiency of visual processing by asking: How is processing altered for information presented at the location of attention? To develop some initial evidence of the stage of processing affected by reflexive visuospatial attention, Chapters 1 to 6 assessed whether this attentional resource is related to four other stimulus-driven effects that are each associated with a specific stage of visual processing: identity processing, object filtering, visual working memory (VWM), and response generation. Based on the observation that only the stimulus-driven effects on VWM are related to reflexive visuospatial attention (i.e., only those effects were contingent on attentional control settings), a VWM model of reflexive visuospatial attention was proposed in Chapter 7, and tested in Chapters 8 to 11. According to this model, reflexive visuospatial attention alters visual processing by triggering VWM to update. Thus, the effect of reflexive visuospatial attention is to speed the encoding of attended information into VWM. As a result, this information is more likely than unattended information to bias our behaviour, in particular those behaviours that depend on VWM. Further, by biasing VWM, reflexive visuospatial attention can interact with other attentional resources that have also been associated with VWM. In this way, these attentional resources can coordinate in optimising the process of selection, thus, contributing to the efficiency of the human visual system.

The efficiency of human visual information processing is supported by numerous attentional resources. These resources ensure that behaviourally relevant information within visual scenes is selected for detailed processing, while behaviourally irrelevant information is ignored. One of these attentional resources—reflexive visuospatial attention—operates by prioritising locations in visual space in response to the appearance of salient stimuli. The purpose of the present dissertation was to examine how this type of attention contributes to the efficiency of visual processing by asking: How is processing altered for information presented at the location of attention? To develop some initial evidence of the stage of processing affected by reflexive visuospatial attention, Chapters 1 to 6 assessed whether this attentional resource is related to four other stimulus-driven effects that are each associated with a specific stage of visual processing: identity processing, object filtering, visual working memory (VWM), and response generation. Based on the observation that only the stimulus-driven effects on VWM are related to reflexive visuospatial attention (i.e., only those effects were contingent on attentional control settings), a VWM model of reflexive visuospatial attention was proposed in Chapter 7, and tested in Chapters 8 to 11. According to this model, reflexive visuospatial attention alters visual processing by triggering VWM to update. Thus, the effect of reflexive visuospatial attention is to speed the encoding of attended information into VWM. As a result, this information is more likely than unattended information to bias our behaviour, in particular those behaviours that depend on VWM. Further, by biasing VWM, reflexive visuospatial attention can interact with other attentional resources that have also been associated with VWM. In this way, these attentional resources can coordinate in optimising the process of selection, thus, contributing to the efficiency of the human visual system.