Made available in DSpace on 2016-04-29T13:18:10Z (GMT). No. of bitstreams: 1 Gisele de Lima Fernandes.pdf: 7708197 bytes, checksum: d2c31d2a5302f3564102245125dc8900 (MD5) Previous issue date: 2005-05-25 / The present experiment is a systematic replication of Ferreira (2002) and aimed to analyze the choice behavior in typical developing children through the simultaneous variation of reinforcer magnitude and delay. The participants, 6 five to six year-old children who studied at a public state pre-school, were exposed to a computer choice task programmed in concurrent-chains schedule. In the initial link, there was a VI 15s schedule independently programmed in each component. Subsequently, in the baseline condition, each component was programmed to produce high and low reinforcer magnitude with the same delay (magnitude baseline) and long and short reinforcer delay with the same magnitude (delay baseline) and, in the experimental condition, there was a simultaneous variation of reinforcer magnitude and delay. There were 4 phases in the experimental condition, in which the short delay was kept at 5s, but the long delay was progressively increased throughout the phases (25s phase 1, 35s phase 2, 45s phase 3, 55s phase 4. The delay period was programmed in Fixed Time (FT). At the end of the Fixed Time, the reinforcement was made available. Tokens in different sizes and colors were used as reinforcers (big green token corresponded to high magnitude and small white token to low magnitude); they were produced in a FR5 schedule and were exchangeable for toys at the end of the session. Five high magnitude tokens were exchangeable for two toys and five low magnitude tokens were exchangeable for one toy. The results show that, although the children responded in the component that produced high reinforcer magnitude over the one that produced low magnitude (magnitude baseline) and in the component that produced a short reinforcer delay over the one that produced long delay (delay baseline) in most the trials of the baseline conditions, when these variables were simultaneously varied, the children responded more frequently in the component that produced higher reinforcer magnitude, although they were delayed, even with the increase up to 55s in delay through the phases. The data were discussed in terms of the possible interference of the procedures adopted and the reinforcing properties of the tokens, toys, and the response of using the computer over the choice and self-control behavior. / O presente experimento trata de uma replicação sistemática de Ferreira (2002) com o objetivo de analisar o comportamento de escolha em crianças com desenvolvimento típico, a partir da variação simultânea da magnitude e do atraso do reforço. Os participantes, 6 crianças com idade de 5 a 6 anos estudantes de uma pré-escola de Ensino Público Estadual, foram expostos a uma atividade de escolha programada em esquema encadeado concorrente num computador. No elo inicial foi programado em cada um dos componentes, de modo independente, um esquema VI 15s. Posteriormente, na condição de linha de base cada um dos componentes era programado para produzir de forma distinta magnitude alta e baixa do reforço com atraso igual (linha de base magnitude) e atraso maior e menor do reforço com magnitude igual (linha de base atraso) e, na condição experimental, houve a variação simultânea da magnitude e do atraso do reforço. Na condição experimental foram manipuladas 4 fases, sendo que o atraso menor permaneceu constante (5 segundos), mas o atraso maior foi aumentado progressivamente no decorrer das fases (25 segundos fase 1, 35 segundos fase 2, 45 segundos fase 3 e 55 segundos fase 4). O período de atraso do reforço foi programado por Tempo Fixo (FT). Ao final do Tempo Fixo entrava em vigor o período de acesso ao reforço. Utilizou-se como reforço fichas de cores e tamanhos diferentes (ficha grande e verde correspondia à magnitude alta e ficha pequena e branca correspondia à magnitude baixa), ganhas num esquema FR5, que eram trocadas por brinquedos no final da sessão. Cinco fichas de magnitude alta eram trocadas por dois brinquedos e cinco fichas de magnitude baixa eram trocadas por um brinquedo. Os resultados encontrados revelam que, embora na fase de linha de base as crianças na maioria das tentativas responderam no componente que produzia magnitude alta sobre o que produzia magnitude baixa do reforço (linha de base magnitude) e no componente que produzia atraso menor sobre o componente que produzia atraso maior do reforço (linha de base atraso), quando houve manipulação simultânea dessas variáveis, responderam mais freqüentemente no componente que produzia magnitude alta do reforço apesar do atraso maior, mesmo com o aumento através das fases, chegando até 55 segundos. Os dados obtidos são discutidos nos termos da possível interferência dos procedimentos adotados e das propriedades reforçadoras das fichas, dos brinquedos e do próprio manusear do computador para a apresentação do comportamento de escolha de autocontrole.

Made available in DSpace on 2016-04-29T13:18:12Z (GMT). No. of bitstreams: 1 Diana Alvim Pena Canavarros.pdf: 510987 bytes, checksum: c4c68992eb0813d2f9d82230c43c1bca (MD5) Previous issue date: 2009-05-14 / This study was carried out in order to analyze the behavior of self-control in children, comparing two types of procedure of gradual change: the procedure of gradual increase in the period of delay of greater reinforcement magnitude (fading in) and the procedure to decrease progressive period of delay in the reinforcement of smaller magnitude (fading out); for that, were analyzed competing schemes linked with components programmed for different magnitudes and delays of reinforcement. Ten children aged between seven and twelve years old participated in the study which involved activities on a computer with a program specially developed for this research. In the first link of the competitor chained scheme, a response in the selected component, producing, on a variable interval of 10 seconds, the second link in the chain, which consisted of a fixed time (the period of delay of reinforcement), in which the computer screen remained dark. The period of delay of reinforcement varied as the experimental condition programmed, from 1 second to 150 seconds. The third link in the chain was started with the appearance of a red square, and a response of clicking with the mouse produced the release of dots. All ten subjects participated in two initial conditions for the evaluation of sensitivity to differences in magnitude and delay of reinforcement. There were two different conditions of variation in the period of delay of reinforcement. Four participants were exposed to a condition in which the delays of the greater magnitude of reinforcement (3 points) were gradually increased (1s, 30s, 75s, 120s, 150s), while the component of lesser magnitude of reinforcement (1 point) remained constant, without variation (1s). Six participants were exposed to a condition in which the delays of the lower magnitude of reinforcement (1 point) were gradually decreased (150s, 120s, 75s, 30s, 1s, to four participants, 120s, 75s, 30s, 1s, for one participant, and 90s, 75s, 30s, 1s, for one participant), while the most important component of the increase (3 points) remained constant with the initial value of the sequence of delay indicated (150s, 120s and 90s, respectively). All ten participants showed differences in sensitivity in terms os difference of magnitude of delay of reinforcement, the two conditions of assessment, with some differences in the number of sessions per participant. In relation to the gradual increase of the delay of the greatest magnitude of reinforcement, the results show that most participants preferred for the component of impulsivity. In the condition of progressive reduction of the delay of the smaller magnitude of reinforcement, all six participants showed preference for the component of self-control. Only when the delay of the component of smaller magnitude of reinforcement decreased to 1 second, the majority of participants chose the component of impulsivity. It was found that the determinant factor is not the delay time itself, but the relative difference of values of delay between the two components / O presente estudo foi realizado com o objetivo de analisar o comportamento de autocontrole em crianças, a partir da comparação entre dois procedimentos de mudança gradual: o procedimento de aumento progressivo no período de atraso do reforço de maior magnitude (fading in) e o procedimento de diminuição progressiva no período de atraso do reforço de menor magnitude (fading out); para tanto foram analisadas escolhas em esquemas concorrentes encadeados, com componentes programados para diferentes magnitudes e atrasos do reforço. Dez crianças com idades entre sete e doze anos participaram do estudo que envolveu a realização de atividades em um computador, a partir de um programa especialmente desenvolvido para esta pesquisa. No primeiro elo do esquema concorrente encadeado, uma resposta no componente selecionado, produzia, em intervalo variável de 10 segundos, o segundo elo da cadeia, que consistia em um tempo fixo (o período de atraso do reforço), em que a tela do computador permanecia escura. O período de atraso do reforço variava, conforme a condição experimental programada, de 1 segundo a 150 segundos. O terceiro elo da cadeia era iniciado com o aparecimento de um quadrado vermelho e uma resposta de clicar com o mouse nesse quadrado produzia a liberação de pontos. Todos os dez participantes foram submetidos a duas condições iniciais de avaliação da sensibilidade a diferenças de magnitude e atraso do reforço. Houve duas condições diferentes de variação no período de atraso do reforço. Quatro participantes foram expostos a uma condição em que os atrasos do componente de maior magnitude do reforço (3 pontos) foram aumentados progressivamente (1s; 30s; 75s; 120s; 150s), enquanto que o componente de menor magnitude do reforço (1 ponto) permaneceu constante, sem variação (1s). Seis participantes foram expostos a uma condição em que os atrasos do componente de menor magnitude do reforço (1 ponto) foram diminuídos progressivamente (150s; 120s; 75s; 30s; 1s, para quatro participantes; 120s, 75s; 30s; 1s, para um participante, e 90s; 75s; 30s; 1s, para um participante); enquanto que o componente de maior magnitude do reforço (3 pontos) permaneceu constante com o valor inicial da sequência de atraso indicada (150s, 120s e 90s, respectivamente). Todos os dez participantes apresentaram sensibilidade as diferenças de magnitude e de atraso do reforço, nas duas condições de avaliação, com algumas diferenças no número de sessões realizadas por participante. Em relação à condição de aumento gradual do atraso do componente de maior magnitude do reforço, os resultados demonstram que a maioria dos participantes apresentou preferência pelo componente de impulsividade. Na condição de diminuição progressiva do atraso do componente de menor magnitude do reforço, todos os seis participantes, apresentaram preferência pelo componente de autocontrole. Somente quando, o atraso do componente de menor magnitude do reforço diminuiu para 1 segundo, a maioria dos participantes escolheu o componente de impulsividade

Made available in DSpace on 2016-04-29T13:18:15Z (GMT). No. of bitstreams: 1 Tatiana Chagas Correia.pdf: 664085 bytes, checksum: edd240a61f1fb247e5c51f651c8c476d (MD5) Previous issue date: 2009-06-16 / This experiment was conducted in order to investigate whether the presentation of a temporal marker for the period of delay of reinforcement increases the probability of choosing the component related to greater magnitude and greater delay of reinforcement, when it is presented along with a component related to less delay and magnitude. The participants, 9 children aged between 8 and 10 years were exposed to concurrent-chains schedule in the computer. In the original link were scheduled in each component schemes VI10s independent. The first response after a variable interval of 10s produced the beginning of FT (2nd link), with a marker time (clock) with a stimulus not related to changes with passage of time (non-clock) or with blackout. The third link was initiated soon after the end of the delay and gave access to the acquisition of points. Participants were subjected to two conditions for evaluating the sensitivity to differences in magnitude and delay. The first component was programmed to produce a distinct form of greater and lesser delay with equal magnitude and a higher and lower magnitude with equal delay in the second evaluation. In the experimental condition were varied at the same time delay and magnitude of reinforcement. In this condition the least delay and magnitude remained constant (1s and 1 point), while the largest was between 30s, 75s, 120s or 45s, 90s, 135s and the magnitude remained constant (3 points). There were three sequences of values of delay (one with progressive increase of delay), and the same sequence was exposed to three participants. Participants were divided into three groups, with the Group C was exposed to this variation and the screen during the FT off (blackout), the Group A was initially exposed to this variation, the first condition, in the presence of clock and then the second condition in the presence of non-clock during the FT and Group B was exposed to the reverse order of Group A. Every 3 points earned could be exchanged for a free gift. The results indicate that there were high rates of response to selection in the component of larger delay and larger magnitude self-control when the value of the largest delay was 30s or 45s when it was presented in the first condition, but not with higher values as 75s, 120s, 90s and 135s. There were falls in the rate of responses on the component of self-control in the course of experimental sessions and the second presentation of the sequence of values of the delay. This pattern of responses was similar to almost all participants of the three groups. The results are discussed in terms of the number of answers to choose, in the presence of the clock, non-clock or the blackout period in FT, the sequence of delays that participants were exposed and the number of sessions in each condition. There were no relations between the operations performed during the FT - blackout, clock and non-clock and choice of the larger delay and larger magnitude / O presente experimento foi realizado com objetivo de investigar se a apresentação de um marcador temporal durante o período de atraso do reforço aumenta a probabilidade de escolha pelo componente relacionado com maior magnitude e maior atraso do reforço, quando este é apresentado junto com um componente relacionado a menor atraso e magnitude. Os participantes, 9 crianças com idade entre 8 e 10 anos, foram expostos ao esquema concorrente-encadeado no computador. No elo inicial foram programados em cada componente esquemas de VI10s independentes. A primeira resposta após o intervalo variável de 10s produzia o início do período de FT (2º elo), com um marcador temporal (relógio), com um estímulo com alterações não relacionadas à passagem do tempo (não-relógio) ou com blackout. O terceiro elo tinha início logo após o fim do período de atraso e dava acesso à aquisição de pontos. Os participantes foram submetidos a duas condições de avaliação da sensibilidade a diferenças de atraso e magnitude, sendo que na primeira cada componente era programado para produzir de forma distinta atraso maior e menor com magnitude igual e magnitude maior e menor com atraso igual na segunda avaliação. Na condição experimental foram variadas simultaneamente atraso e magnitude do reforço. Nesta condição o menor atraso e magnitude permaneceram constantes (1s e 1 ponto), enquanto que o maior atraso variou entre 30s, 75s, 120s ou 45s, 90s, 135s e a magnitude permaneceu constante (3 pontos). Havia três seqüências de valores de atraso (uma delas com aumento progressivo do atraso), sendo que a mesma seqüência foi exposta para três participantes. Os participantes foram divididos em três grupos, sendo que o Grupo C foi exposto a esta variação tendo a tela no período de FT apagada (blackout), o Grupo A foi exposto a esta variação inicialmente, na primeira condição, com a presença do relógio no FT e posteriormente, na segunda condição, com a presença do não-relógio durante o FT e o Grupo B foi exposto à ordem inversa do Grupo A. Cada 3 pontos ganhos poderiam ser trocados por um brinde. Os resultados encontrados indicam que ocorreram altas taxas de respostas de escolha no componente de maior atraso e maior magnitude autocontrole quando o valor do maior atraso era 30s ou 45s quando este era apresentado na primeira condição, mas não com valores maiores como 75s, 120s, 90s e 135s. Houve quedas na taxa relativa de respostas no componente de autocontrole no decorrer das sessões experimentais e na segunda apresentação da seqüência de valores do atraso. Este padrão de respostas foi semelhante à quase todos os participantes dos três grupos. Os resultados são discutidos em termos do número de respostas de escolha, na presença do relógio, do não relógio ou do blackout no período de FT, da seqüência de atraso a que os participantes foram expostos e do número de sessões realizadas em cada condição. Não foram observadas relações entre as manipulações feitas durante o FT blackout, relógio e não relógio e a escolha do componente de maior atraso e maior magnitude

Made available in DSpace on 2016-04-27T17:27:25Z (GMT). No. of bitstreams: 1 Manucia Passos de Lima.pdf: 748451 bytes, checksum: d159bd2b478033f59f3f684cbeabc5b2 (MD5) Previous issue date: 2008-10-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This research approaches the process of habit-change in the thought of Peirce (1839-1914) starting from the hypothesis that there is a strong relation between self-control and pragmatism and that habit-change takes place by a stimulus, even though vague, to use reason with the aim of reaching a coherent and admirable conduct. Peirce who was a well-known chemist with a vast experience in laboratory and owner of an eclectic mind very well trained in Logic and Philosophy is considered as one of the greatest American thinkers and the father of pragmatism. Pragmatism which is a method that aims apprenticeship and evolution e that can be used to guide thought to higher levels of clarity has a normative realm as it aims deliberate conduct, which is conscious and self-controlled. In this research it was observed that the habit conception, which is that specialization of the law of mind whereby a general idea gains the power of exciting reactions (CP 6.145) is fundamental in Peirce´s pragmatism. It was also observed that the tendency to acquiring habits as an evolution principle has in its essence a tendency to change since evolution does not happen without habit-change and vice-versa. Through evolutionary habit-change, that inspires itself in an admirable ideal, which is also under evolution, tends to rational self-control and takes place in daily practice deliberate by logic / Esta pesquisa aborda o processo de mudança de hábitos no pensamento de Peirce (1839-1914) partindo da hipótese de que há uma forte relação entre autocontrole e pragmatismo e de que mudança de hábitos se dá por um estímulo, mesmo que vago, para se aplicar a razão objetivando alcançar uma conduta coerente e admirável. Peirce que foi um renomado químico com muita experiência em laboratório e possuidor de uma mente multidisciplinar que conhecia bem Lógica e Filosofia é considerado como um dos maiores pensadores americanos bem como o pai do pragmatismo. Pragmatismo que é um método que visa aprendizagem e evolução e que pode ser utilizado para encaminhar o pensamento para níveis mais elevados de clareza tem um teor normativo já que se interessa por conduta deliberada, que é consciente e autocontrolada. Nesta pesquisa se observou que o conceito de hábito, que é aquela especialização da lei da mente por meio da qual uma idéia geral ganha o poder de ativar reações (CP 6.145), é fundamental no pragmatismo de Peirce. Observou-se também que sendo a tendência ao hábito um princípio evolutivo ela traz em sua essência uma tendência à mudança uma vez que evolução não acontece sem mudança de hábitos e vice-versa. Ao longo da evolução a mudança de hábitos, que se inspira num ideal admirável que também se submete à evolução, tende para o autocontrole e se viabiliza na prática cotidiana ponderada pela lógica

Considerando a escassez de trabalhos científicos relacionados às medidas de biosseguridade na área de peixes ornamentais, o presente estudo utiliza o Sistema APPCC para delinear a criação e implementação de programas de autocontrole sanitário em estabelecimentos atacadistas de peixes ornamentais, estabelecendo os seguintes objetivos: 1) criar um guia de orientação para a adoção de medidas de biosseguridade relacionadas às boas práticas de manejo e higiene em comércio atacadista de peixes ornamentais; 2) listar os principais perigos biológicos de natureza bacteriana, viral, fúngica e parasitária aos quais os peixes ornamentais estão susceptíveis, bem como as medidas de prevenção e controle e 3) aplicar o Sistema APPCC em comércio atacadista de peixes ornamentais para um efetivo autocontrole sanitário dos animais comercializados. Como metodologia seguiram-se os passos para implementação do Sistema APPCC respectivamente: 1) identificação da empresa e definição do âmbito de aplicação, acompanhamento dos colaboradores e identificação das funções, das condições de infraestrutura e práticas higiênicossanitária, descrição do produto, elaboração de um fluxograma da área de processamento desde o recebimento até a expedição e validação in loco do Fluxograma; 2) identificação dos perigos biológicos e medidas preventivas para controle; 3) determinação dos pontos críticos de controle, estabelecimento de limites críticos de controle, monitoramento, ações corretivas; procedimentos de verificação e registro de dados e documentação. Conclui-se, que o Sistema APPCC é aplicável e útil para o autocontrole sanitário em comércio atacadista de peixes ornamentais e, como um programa de autocontrole serve de base para criação de outros programas relacionado às boas práticas, tais como controle higiênicossanitário e Bem Estar Animal, aumentando a qualidade técnico-produtiva do negócio e oferecendo animais saudáveis ao consumidor / Due to the scarcity of scientific studies related to biosecurity measures in the ornamental fish area, this current study works under the HACCP System to delineate the creation and implementation of sanitary control programs in wholesale ornamental fish, establishing the following objectives: 1) to create a guideline for the implementation of biosecurity measures related to good management and hygiene practices in wholesale trade for ornamental fish; 2) to list the main biological hazards of bacterial, viral, fungal and parasitic to which ornamental fish are susceptible, as well as the prevention and control measures; and 3) to apply the HACCP system in wholesale trade in ornamental fish for effective sanitary control of the sold animals. As a methodology, the following steps were taken in order to implement the HACCP System: 1) identification of the company and definition of the scope, monitoring of employees and identification of functions, infrastructure conditions and hygienic sanitary practices, product description, elaboration of a flow diagram from the processing area from receipt to expedition and on-site validation of the flow diagram; 2) identification of biological hazards and preventive measures for control; 3) determination of critical control points, establishment of critical limits of control, monitoring, corrective actions; procedures for verification and recording of data and documentation. It is concluded that the HACCP system is applicable and useful for sanitary self-control in wholesale trade in ornamental fish, and since a self-control program serves as a basis for the creation of other programs related to good practices such as hygienic sanitary control and Animal Welfare, increasing the technical-productive quality of the business and offering healthy animals to the costumer.

Despite the criminal nature of intimate partner violence, scholars infrequently apply general theories of crime to understanding its causes (Dixon, Archer, & Graham-Kevan, 2012). Indeed, some scholars reject the notion that the causes of intimate partner violence align with the causes of general crime and violence (Dobash, Dobash, Wilson, & Daly, 1992). A second area of contention is whether male and female violence can be explained within the same theoretical framework (Dutton & Nicholls, 2005). In this thesis I argue that as a type of criminal behaviour, understanding the causes of intimate partner violence from a criminological perspective is a valid and necessary research endeavour. Further, guided by the principles of the theoretical framework of this thesis, I submit that both male and female intimate partner violence can be explained within the same general theory of crime. This thesis applies situational action theory, a general theory of crime that places morality at the centre of its explanatory framework, to the understanding and explanation of intimate partner violence. This thesis concentrates on the roles of personal morality and provocation in intimate partner violence perpetration. Partner conflict is defined as the experience of provocation, while friction sensitivity and low partner cohesion are included as key factors leading to partner conflict. Specifically, this thesis examines whether the strength of personal morality influences whether individuals respond to provocation with violence against a partner. To address the aims of the research, this thesis uses data from the Peterborough Adolescent and Young Adult Development Study, a study designed to test situational action theory. Participants are a representative sample of males and females between 24 and 25 years of age. Path analyses using a multiple-group method revealed that high friction sensitivity and low partner cohesion contributed to increased partner violence perpetration by influencing the level of partner conflict. Morality had a significant moderating effect on the path between partner conflict and partner violence perpetration. Namely, individuals with weak morality, and who frequently engaged in partner conflict, were significantly more likely to perpetrate acts of partner violence than individuals with strong morality who engaged in frequent conflict with a partner. These findings were replicated across males and females. The findings of this research illustrate the importance of morality in the explanation of partner violence, and provide evidence that both male and female partner violence can be explained within the framework of situational action theory.

School readiness incorporates children's academic abilities and their ability to self-regulate in the classroom. Prior research shows that sleep is related to children's development of these skills, although the mechanisms through which sleep affects school readiness are not well understood. Research also indicates that economically disadvantaged children and children of color may have poorer academic and regulatory skills at school entry and may sleep less and sleep less well on a regular basis. The current study explores the role of sleep quantity and quality in young children's development of two skills critical for school success: self-regulation and academic abilities. This study intentionally focuses on a predominantly African-American, economically disadvantaged population, who may be at risk for greater sleep-related difficulties and lower school-related skills at kindergarten entry. It was hypothesized that a) young children with higher quantity and quality of sleep would show greater development of academic skills and self-regulation across one calendar year, b) the role of sleep in the development of these abilities would be relatively stronger among kindergarteners than among 1st graders, and c) the role of sleep quality and quantity in young children's development of academic abilities would be partially explained by the relation between sleep and self-regulation. Results provide mixed support for the hypotheses, indicating that sleep quality and quantity relate differentially to different school-related skills among kindergarteners and 1st graders. This study contributes research to help explain how and why sleep affects young children and may offer insights for caregivers and educators working to help children develop school-related skills.

This dissertation study attempts to understand excessive buying, a phenomenon of both theoretical and practical interest. I define excessive buying as "an individual type of buying behavior whereby consumers repetitively spend more than they should based on financial considerations". I develop a conceptual typology of excessive buying, building on the time-inconsistent preferences and automaticity theory. The new typology categorizes five specific types of excessive buying behavior: 1) habitual, 2) possessive, 3) remedial, 4) rewarding, and 5) out-of-control. Based on past literature and the typology, I generate scale items to capture the conceptual and logical variance in excessive buying. Psychometric properties of the scale are tested via Confirmatory Factor Analysis using a student and random adult sample. Nomological validity of the scale is confirmed by testing hypotheses formulated based on hedonic shopping values and the self-defeating behavior theory. The empirical analyses suggest that excessive buying results from stress, using shopping as an escape from reality, and little consideration for the potential outcomes of one's current behavior. Excessive buying leas to both financial problems and negative emotions.

Research indicates that preschool experience significantly influences child development and this study examined the influence of preschool learning experiences on children’s school readiness, self-regulation and academic achievement. Participants were 190 children from an impoverished county in Southwest China and their teachers. Classroom observations were conducted and children were assessed in individual and group sessions. There were three different types of preschool programs (kindergartens, pre-primary classes; Grade 1) available in the county. A total of 18 teaching episodes provided in either the kindergarten or primary schools to 164 children were videotaped and analyzed. Results indicated marked variations in preschool quality and pedagogical practices to support children’s self-regulation across programs. Kindergartens had the best physical environments, the most resources and highly qualified teachers. The teachers provided children with meaningful learning opportunities, adequate instructions, clear structure and predictability, and diversified instructional formats. Pre-primary classes had limited resources and unqualified teachers who emphasized academic learning. Compared to kindergarten teachers, pre-primary class teachers prepared fewer activities and frequently required children to simply sit still and listen. Preschool age children who merely “sat in” Grade 1 classrooms were typically neglected by teachers and only received attention from the teacher when they were disruptive. Grade 1 children (89 girls) who had attended kindergarten (n = 60), separate pre-primary classes (n = 55), merely “sat in” Grade 1 classes before being formally enrolled in school (n = 54) or had no preschool experience (n = 21) were assessed at the beginning of Grade 1 (Wave 1), at the end of Grade 1 (Wave 2), and at the end of Grade 2 (Wave 3). Their school readiness was assessed in Wave 1. Their self-regulation skills were assessed using the modified Head-Toes-Knees-Shoulders task in Waves 1 and 2, and seven cognitive regulation tests in Wave 3. Their literacy and mathematics achievement was evaluated using curriculum-based tests across the three waves. Results indicated that children with some form of preschool experience outperformed those with none in almost all the three outcomes across the three waves. Children from the kindergarten had better school readiness than the other three groups and better self-regulation than those attending separate pre-primary classes at the start of school. Children attending separate pre-primary classes had significantly better literacy and mathematics than those from the kindergarten at the start of school and literacy at the end of Grade 2. Children “sitting in” Grade 1 classes achieved lower scores than those from the kindergarten and pre-primary classes on almost all child outcome measures. The growth of self-regulation within the first primary school year was significant and Wave 1 behavioral regulation predicted Wave 3 cognitive regulation. School readiness and self-regulation significantly predicted academic achievement in all three waves and school readiness mediated the close relationship between self-regulation and academic achievement. Findings highlight the importance of (i) preschool experience for children from economically disadvantaged families in rural China; and (ii) self-regulation in school preparedness and early academic attainment. They also have implications for scaling up and enhancing the quality of preschool programs. / published_or_final_version / Education / Doctoral / Doctor of Philosophy

In der vorliegenden Studie wurde mittels der Bildgebung des funktionellen MRT die Dynamik der neuronalen Hirnmechanismen untersucht, die es dem Menschen erlauben, durch kurzfristigen Verzicht auf Belohnungen seinen Verhaltenserfolg langfristig zu optimieren. Durch den Vergleich zweier Extremgruppen gesunder Probanden (hoch- versus niedrig- impulsive Probanden) sollte ein möglicher Zusammenhang zwischen der Impulsivität und dem funktionellen Zusammenspiel frontostriataler Regelkreise während des aktiven Prozesses der Entscheidungsfindung dargestellt werden. Die vorliegende Studie hat gezeigt, dass gesunde, nicht- klinische Individuen, die sich selbst mittels der Barratt- Impulsivitätsskala als hoch- impulsiv charakterisiert haben, ihr Verlangen nach einer direkten Belohnung erfolgreich durch Aktivierung zweier komplementärer Hirnmechanismen kontrollieren können. Als erster Mechanismus ist festzuhalten, dass selbstkontrollierte Entscheidungen zu einer Abschwächung der belohnungsabhängigen Aktivierung im Nucleus accumbens führten, welche von einer ansteigenden inversen Verbindung mit dem anteroventralen präfrontalen Kortex begleitet wurde. Der zweite Mechanismus ist, dass HI- Probanden ihren Wunsch nach einer höherwertigen, aber suboptimalen Belohnung in Abhängigkeit von der Wertigkeit der unmittelbaren Belohnung durch Downregulation im ventromedialen präfrontalen Kortex kontrollierten. Diesem Mechanismus folgte eine ansteigende inverse Kopplung mit dem ventralen Striatum. Von entscheidender Bedeutung ist dabei, dass sich diese neuronalen Mechanismen qualitativ von denen der extrem- kontrollierten Probanden unterschieden. Insgesamt lässt sich sagen, dass diese Ergebnisse darauf hindeuten, dass es persönlichkeitsspezifische neuronale Mechanismen gibt, die es hoch-impulsiven Probanden ermöglichen, ihren Wunsch nach einer unmittelbaren Belohnung zu kontrollieren.