Information processing in the brain is governed by oscillatory activity. Activity oscillations in specific frequency bands (theta, alpha, beta and gamma) have been associated with various cognitive functions. A drawback of this is that the plethora of findings led to considerable uncertainty as to the functional relevance of activity in different frequency bands and their interrelation. Here, we use a novel cognitive-science theoretical framework to better understand and conceptually harmonize neurophysiological research on human action control. We outline how this validated starting point can systematize and probably reframe the functional relevance of oscillatory activity relevant for action control and beyond.

A multitude of sensory inputs needs to be processed during sensorimotor integration. A crucial factor for detecting relevant information is its complexity, since information content can be conflicting at a perceptual level. This may be central to executive control processes, such as response inhibition. This EEG study aims to investigate the system neurophysiological mechanisms behind effects of perceptual conflict on response inhibition. We systematically modulated perceptual conflict by integrating a Global-local task with a Go/Nogo paradigm. The results show that conflicting perceptual information, in comparison to non-conflicting perceptual information, impairs response inhibition performance. This effect was evident regardless of whether the relevant information for response inhibition is displayed on the global, or local perceptual level. The neurophysiological data suggests that early perceptual/ attentional processing stages do not underlie these modulations. Rather, processes at the response selection level (P3), play a role in changed response inhibition performance. This conflict-related impairment of inhibitory processes is associated with activation differences in (inferior) parietal areas (BA7 and BA40) and not as commonly found in the medial prefrontal areas. This suggests that various functional neuroanatomical structures may mediate response inhibition and that the functional neuroanatomical structures involved depend on the complexity of sensory integration processes.

Executive functions, like the capacity to control and organize thoughts and behavior, develop from childhood to young adulthood. Although task switching and working memory processes are known to undergo strong developmental changes from childhood to adulthood, it is currently unknown how task switching processes are modulated between childhood and adulthood given that working memory processes are central to task switching. The aim of the current study is therefore to examine this question using a combined cue- and memory-based task switching paradigm in children (N = 25) and young adults (N = 25) in combination with neurophysiological (EEG) methods. We obtained an unexpected paradoxical effect suggesting that memory-based task switching is better in late childhood than in young adulthood. No group differences were observed in cue-based task switching. The neurophysiological data suggest that this effect is not due to altered attentional selection (P1, N1) or processes related to the updating, organization, and implementation of the new task-set (P3). Instead, alterations were found in the resolution of task-set conflict and the selection of an appropriate response (N2) when a task has to be switched. Our observation contrasts findings showing that cognitive control mechanisms reach their optimal functioning in early adulthood.

La consommation énergétique dans le secteur bâtiment dépend de diverses facteurs parmi lesquels ses caractéristiques physique, ses équipements, l’environnement extérieur, etc… mais il ne faut pas oublier le comportement des habitants qui est déterminant pour la consommation énergétique globale. Or, la plupart des travaux et outils représentent les occupants par des profils d’occupation. Cette thèse s’intéresse à la représentation plus détaillée du comportement des occupants, en particulier les mécanismes cognitifs, réactifs et délibératifs. Le comportement dynamique des occupants est modélisé et co-simulé avec les aspects physiques et des éventuels systèmes de gestion énergétique. L’analyse de la consommation de différents équipements électroménagers met en évidence que le consommation énergétique est très dépendante des comportements des occupants. L’analyse des consommations et des actions des habitants permet d’élaborer un modèle du comportement des occupants impactant la consommation énergétique. Le modèle représente des mécanismes cognitifs, qui représente les causes qui motivent les actions, incluant des échange avec d’autres acteurs humains. Une approche à base d’agents logiciels a été développée. Outre les aspects techniques, une méthodologie de réglage des paramètres des modèles de comportement est proposée. Ces outils sont utilisés pour réaliser une co-simulation représentant la physique du bâtiment, le comportement réactif, c’est-à-dire sensible aux données physiques, et délibératif des habitants mais aussi un système de gestion énergétique qui peut ajuster directement la configuration du logement ou simplement conseiller ces occupants. L’impact de différents types de comportements, avec et sans gestionnaire énergétique est analysé. Ces travaux ouvrent de nouvelles perspectives dans la simulation bâtiment, dans la validation de gestionnaires énergétiques mais aussi dans la représentation des bâtiments dans les réseaux d’énergie dits intelligents, dans lesquels des signaux peuvent être envoyés aux utilisateurs finaux pour les inviter à moduler leur consommation. / Energy consumption in buildings is affected by various factors including its physical characteristics, the appliances inside, and the outdoor environment, etc. However, inhabitants’ behaviour that determines the global energy consumption must not be forgotten. In most of the previous works and simulation tools, human behaviour is modelled as occupancy profiles. In this thesis the focus is more on detailed behaviour representation, particularly the cognitive, reactive, and deliberative mechanisms. The inhabitants’ dynamic behaviour is modelled and co-simulated together with the physical aspects of a building and an energy management system. The analysis of different household appliances has revealed that energy consumption patterns are highly associated with inhabitants’ behaviours. Data analysis of inhabitants’ actions and appliances’ consumptions is used to derive a model of inhabitants’ behaviour that impacts the energy consumption. This model represents the cognitive mechanisms that provide causes that motivate the actions, including the communication with other inhabitants. An approach based on multi-agent systems is developed along with a methodology for parameter tuning in the proposed behaviour model. These tools are used to co-simulate, not only the physical characteristics of the building, the reactive behaviour that is sensitive to physical data, and deliberative behaviour of the inhabitants, but also the building energy management system. The energy management system allows the direct adjustment of the building parameters or simply giving advice to the inhabitants. The impact of different types of inhabitants’ behaviours, with and without the inclusion of an energy management system is analyzed. This work opens new perspectives not only in the building simulation and in the validation of energy management systems but also in the representation of buildings in the smart grid where signals can be sent to end users advising them to modulate their consumption.

There is a paucity of South African data concerning the cross-cultural incidence of attitudes and behaviours associated with eating disorders. Research in this area has recognised that acculturation to a Western value system appears to have a pathogenic impact on the prevalence of disordered eating among non-Western ethnic groups. This study aimed to explore the relationship between acculturation and disordered eating, and to compare the level of disordered eating (as measured by the Eating Disorders Inventory [EDI]) among black and white female university students in KwaZulu-Natal. The roles of Body Mass Index (BMI) and socioeconomic status were also examined. The sample consisted of one hundred and twenty-two white female undergraduate students from the University of Natal (Pietermaritzburg), fifteen black female undergraduate students from the University of Natal (Pietermaritzburg), and one hundred and fifty-four black female undergraduate students from the University of Zululand. It was found that although black subjects obtained significantly higher scores on the Drive for Thinness subscale of the EDI, white subjects obtained significantly higher scores on a combination of the three subscales designated to assess disordered eating attitudes and behaviours. Black subjects obtained significantly higher BMI scores than white subjects, and BMI was positively correlated with Body Dissatisfaction in both groups, and with Drive for Thinness in the white group only. No relationship was found between socioeconomic status and disordered eating. Similarly, no relationship was found between acculturation and disordered eating. This latter result is partly a function of problems experienced with the measures of acculturation. A comparison of black subjects from the two universities suggests that greater contact with white students is influential in terms of the development of disordered eating. The above results are discussed in terms of the available literature, and recommendations for future research are made on the basis of the limitations of this study. The data from this study is included in a nation wide cross-cultural study of eating disorders initiated by the Eating Disorders Co-ordinating Committee. / Thesis (M.A.)-University of Natal, Pietermaritzburg, 1996.

A total sample of 1,105 students from the universities of Natal, Witwatersrand and the North participated in this study. The Eating Attitude Test (EAT) and the Bulimic Investigatory Test, Edinburgh (BITE) were administered to three female and three male student samples. Subjects also provided biographic, demographic and weight-related information. The majority of subjects fell within the average weight range of the Body Mass Index (BMI), with the percentage of underweight Indian subjects being higher than the corresponding percentages of the black and white student groups. The majority of males in each race group have accurate weight perceptions. In contrast, the minority of females (fewer than a third) of Indian and white females and under half of black females have accurate weight perceptions. However, all overweight white females assessed themselves as such and 89% of overweight black women assessed themselves as overweight. In terms of exaggerated weight perceptions, more white and Indian females (72% and 70% respectively) consider themselves as overweight or very overweight when they were actually of average weight, than black females (47%). Females in each race group scored consistently higher on all scales assessed than their male counterparts. White females exhibited the most disturbed eating behaviours and attitudes in terms of the categorised percentage scores obtained on all scales of the BITE and EAT. No Indian males obtained scores in the pathological range. On the EAT scale, 19% of white females, 17% of black females and 9% of Indian females, 7% of black males and 1% of white males obtained scores which were categorised as pathological. The more stringent criteria of the BITE showed a lower percentage of all subjects in the pathological range, albeit still retaining the gender discrepancy. Thirteen percent of white female students, 8% of black females, 3% of Indian females, 2% of white males and 1% of black males obtained a pathological score on the BITE scale. The Indian female and male sample exhibited the healthiest eating behaviours and attitudes relative to the other two racial groups examined. In terms of mean scores a general trend emerged in which black males obtained higher mean scores than white and Indian males, and black females obtained mean scores (which were overall) similar in magnitude to those of white females. The majority of black females who obtained pathological scores were urban raised and were from the upper socio-economic stratum. The majority of white females who obtained pathological scores were from urban backgrounds, had exaggerated weight perceptions and expressed a desire to lose at least 10 kilograms of weight. / Thesis (M.A.)-University of Natal, Pietermaritzburg, 1996.

Understanding human behaviour is key to understanding the spread of epidemics, habit dispersion, and the efficacy of health interventions. Investigation into the patterns of and drivers for human behaviour has often been facilitated by paper tools such as surveys, journals, and diaries. These tools have drawbacks in that they can be forgotten, go unfilled, and depend on often unreliable human memories. Researcher-driven data collection mechanisms, such as interviews and direct observation, alleviate some of these problems while introducing others, such as bias and observer effects. In response to this, technological means such as special-purpose data collection hardware, wireless sensor networks, and apps for smart devices have been built to collect behavioural data. These technologies further reduce the problems experienced by more traditional behavioural research tools, but often experience problems of reliability, generality, extensibility, and ease of configuration. This document details the construction of a smartphone-based app designed to collect data on human behaviour such that the difficulties of traditional tools are alleviated while still addressing the problems faced by modern supplemental technology. I describe the app's main data collection engine and its construction, architecture, reliability, generality, and extensibility, as well as the programming language developed to configure it and its feature set. To demonstrate the utility of the tool and its configuration language, I describe how they have been used to collect data in the field. Specifically, eleven case studies are presented in which the tool's architecture, flexibility, generality, extensibility, modularity, and ease of configuration have been exploited to facilitate a variety of behavioural monitoring endeavours. I further explain how the engine performs data collection, the major abstractions it employs, how its design and the development techniques used ensure ongoing reliability, and how the engine and its configuration language could be extended in the future to facilitate a greater range of experiments that require behavioural data to be collected. Finally, features and modules of the engine's encompassing system, iEpi, are presented that have not otherwise been documented to give the reader an understanding of where the work fits into the larger data collection and processing endeavour that spawned it.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 5 uppsatser.

Projektet hade sin bakgrund i önskan att tillhandahålla en virtuell träningsmiljö för lärare där de kan öva på sin icke-verbala kommunikation med elever. Före det här projektet hade utvecklingen av träningsmiljön lett fram till ett visualiserings-system för ett tredimensionellt virtuellt klassrum med animerade karaktärer samt ett system för upptagning och igenkänning av användarens rörelser. För att en sådan träningsmiljö skall vara användbar krävs dock att de virtuella studenterna uppvisar ett trovärdigt mänskligt beteende. Den här rapporten avhandlar implementationen av mänskligt beteende i agenterna förkroppsligade i visualiseringssystemet. För detta ändamål användes det BDI-baserade multi-agent-systemet Jason tillsammans med inspiration från personlighetsteorin OCEAN, affektionsteorin OCC och beteendearkitekturen PMFserv. Rapporten avhandlar även resultatet av ett experiment som utfördes för att utvärdera systemet. I experimentet blev 16 testpersoner introducerade för två olika lärar-scenarion, varpå de, för var och en av dessa scenarion, fyllde i en enkät om deras upplevelse. / The project had its background in the desire to provide a virtual training environment for teachers in which they can exercise their non-verbal communication (e.g. gestures and orientation) with students. Prior to this project, the development of the training environment had led up to a visualisation system for a 3D virtual classroom with virtual students and a motion recognition system for capturing and recognising the user's movements. For such a training environment to be useful however, the virtual students need to express believable human behaviour. This report covers the implementation of human behaviour in the agents embodied in the visualisation system using the BDI-based Jason multi-agent simulation platform with further inspiration taken from the OCEAN personality theory, the OCC theory of emotions and the PMFserv cognitive architecture. It also covers the results of an experiment that was conducted to evaluate the system. During this experiment, 16 test persons were introduced to two different teaching scenarios and were asked to fill in a questionnaire about their experience after each scenario.

Longitudinal developmental fMRI studies just recently began to focus on within-subject reliability using the intraclass coefficient (ICC). It remains largely unclear which degree of reliability can be achieved in developmental studies and whether this depends on the type of task used. Therefore, we aimed to systematically investigate the reliability of three well-classified tasks: an emotional attention, a cognitive control, and an intertemporal choice paradigm. We hypothesized to find higher reliability in the cognitive task than in the emotional or reward-related task. 104 healthy mid-adolescents were scanned at age 14 and again at age 16 within M = 1.8 years using the same paradigms, scanner, and scanning protocols. Overall, we found both variability and stability (i.e. poor to excellent ICCs) depending largely on the region of interest (ROI) and task. Contrary to our hypothesis, whole brain reliability was fair for the cognitive control task but good for the emotional attention and intertemporal choice task. Subcortical ROIs (ventral striatum, amygdala) resulted in lower ICCs than visual ROIs. Current results add to the yet sparse overall ICC literature in both developing samples and adults. This study shows that analyses of stability, i.e. reliability, are helpful benchmarks for longitudinal studies and their implications for adolescent development.