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Made available in DSpace on 2016-04-29T13:17:48Z (GMT). No. of bitstreams: 1 Daniel Carvalho de Matos.pdf: 1928285 bytes, checksum: af4f3292fac23f3743a9598b8984c643 (MD5) Previous issue date: 2013-05-21 / The purpose of this research was to assess the effects of manipulating reinforcer delay and probability over the choices in simple and chained concurrent schedules and if these effects suggest similarities between these two reinforcer parameters. Four experiments were conducted. 12 psychology students from a private university served as participants, three for each experiment. The Experiments 1 and 2 involved choice trials between concurrent chained schedules with two links, with the manipulation of reinforcer magnitude and delay (Experiment 1) and reinforcer magnitude and probability (Experiment 2). In both experiments, the choice of component A, from the first link, produced, after T seconds (Experiment 1) or after a probability P (Experiment 2), the access to a new choice link between the components R1 with a small immediate reinforcer (Experiment 1) or a small and more probable reinforcer (Experiment 2) versus R2 with a larger delayed reinforcer (Experiment 1) or with a large and less probable reinforcer (Experiment 2). Still in the first link, in case the component B was chosen, after T seconds (Experiment 1) or a probability P (Experiment 2), there was a second link in which only one component was available: R2 with a large delayed reinforcer (Experiment 1) or with a large and less probable reinforcer (Experiment 2). As a result, first the participants went through selection conditions in which the larger reinforcer should be preferred over the small one (for both experiments); the immediate reinforcer should be preferred over the delayed one (Experiment 1) and the more probable reinforcer should be preferred over the less probable one (Experiment 2); the small immediate reinforcer should be preferred over the larger delayed reinforcer (Experiment 1) and the small and more probable reinforcer should be preferred over the larger and less probable one (Experiment 2). After this, all participants from both experiments went through conditions in which preference reversals, to the component with the larger and more delayed reinforcer (Experiment 1) or the component with the larger and less probable reinforcer (Experiment 2), were assessed. In Experiment 1, the variable time (T) between the two links was manipulated, involving 7.5 and 15 seconds. As result, the data revealed that preference reversal occurred for all the three participants from Experiment 1, considering that, only for participant P1, the reversal occurred when the time (T) between the two links was 7.5 seconds. Besides, for two of the participants (P1 and P3), most of the choices, on first link, were made on component B (alternative that was called the commitment choice according to the literature). In Experiment 2, preference reversal was assessed when the probability between the two links was 17%. The data revealed that reversal occurred, in the sense that most of the choices were made on the component with the larger and less probable reinforcer for all the three participants (P5, P6 and P7). Only for one of these participants (P6), the component B, from first link, was the most chosen one in two blocks of trials. Even though the data suggested relations with those that were obtained in Experiment 1, with the suggestion that reinforcer delay and probability share similar effects over the choices in chained concurrent schedules, there was a methodological problem in Experiment 2 that makes the comparison more difficult. The fact that the probability of the passage from the first to the second link was very low (17%) limited the number of trials in which participants had the chance to respond on second link. Consequently, the access to the reinforcers happened in only a few occasions. Experiments 3 and 4 involved choice trials between simple concurrent schedules with the manipulation of reinforcer magnitude and delay (Experiment 3) and reinforcer magnitude and probability (Experiment 4). After selection conditions similar to those from the two previous experiments, the participants went through a condition with concurrent FR / FR schedules (with a ratio that could vary from 10 to 80), in which the preference reversal was assessed. The data revealed that reversal occurred for all participants from Experiment 3 (P7, P8 and P9) with preference of the component with the larger and delayed reinforcer and the same happened for two of the participants from Experiment 4 (P11 and P12). The data suggested similarities between the reinforcer delay and probability parameters, considering their effects over choices in simple concurrent schedules. In both experiments other conditions (CRF, SigFR and FI) were conducted to assess if the response pattern produced by the FR would be changed, with most of the choices made on the other component with the small immediate reinforcer (Experiment 3) or the small and more probable reinforcer (Experiment 4). The data revealed that the change occurred only for two of the participants from Experiment 4 (P11 and P12), reinforcing the similarity with the data from a research conducted previously with pigeons as subjects / O objetivo desta pesquisa foi avaliar o efeito da manipulação dos parâmetros de atraso e probalidade do reforço sobre as escolhas em esquemas concorrentes simples e encadeados e se esses efeitos sugerem semelhanças entre esses dois parâmetros. Quatro estudos foram conduzidos. Participaram 12 estudantes universitários do curso de psicologia, sendo três participantes para cada estudo. Os Estudos 1 e 2 envolveram tentativas de escolha entre esquemas concorrentes encadeados com dois elos, com manipulação de magnitude e atraso do reforço (Estudo 1) e magnitude e probabilidade do reforço (Estudo 2). Em ambos os estudos, a escolha do componente A, do primeiro elo, produzia, após T segundos (Estudo 1) ou em uma dada probabilidade P (Estudo 2), o acesso a um novo elo de escolha entre os componentes R1 com reforço menor imediato (Estudo 1) ou reforço menor e mais provável (Estudo 2) versus R2 com reforço maior atrasado (Estudo 1) ou reforço maior e menos provável (Estudo 2). Ainda no primeiro elo, caso o componente B fosse escolhido, após T segundos (Estudo 1) ou uma dada probabilidade P (Estudo 2), havia um segundo elo em que apenas um componente, o R2' com reforço maior atrasado (Estudo 1) ou maior e menos provável (Estudo 2), estava presente. Como resultado, primeiramente os participantes passaram por condições de seleção em que maior magnitude deveria ser preferida sobre menor magnitude (para ambos os estudos); menor atraso deveria ser preferido sobre maior atraso (Estudo 1) e maior probabilidade deveria ser preferida sobre menor probabilidade (Estudo 2); menor magnitude e menor atraso deveriam ser preferidos sobre maior magnitude e maior atraso (Estudo 1) e menor magnitude e maior probabilidade deveriam ser preferidos sobre maior magnitude e menor probabilidade (Estudo 2). Depois, os participantes de ambos os estudos passaram por condições em que a reversão da preferência para a alternativa com reforço maior atrasado (Estudo 1) e reforço maior e menos provável (Estudo 2) foi avaliada. No Estudo 1, a variável tempo entre os elos (T) foi manipulada, envolvendo 7.5 e 15 segundos. Como resultado, os dados revelaram que a reversão aconteceu para todos os três participantes do Estudo 1, sendo que, apenas para o participante P1, tal reversão já ocorreu com o tempo (T) entre os elos de 7.5 segundos. Além disso, para dois dos participantes (P1 e P3) os maiores percentuais de escolha, no primeiro elo, foram no componente B. No Estudo 2, a reversão da preferência foi avaliada quando a probabilidade (P) entre os elos era de 17%. O dado indica que a reversão ocorreu, no sentido de que a maior parte das escolhas foi da alternativa com reforço maior e menos provável para todos os três participantes (P5, P6 e P7). Apenas para um desses participantes (P6) o componente B do primeiro elo foi o mais escolhido em dois blocos de tentativas. Ainda que esses dados sugiram relações com os que foram obtidos no Estudo 1, com a sugestão de que atraso e probabilidade do reforço apresentariam efeitos semelhantes sobre as escolhas em esquemas concorrentes encadeados, houve diferenças nas taxas de reforços entre os estudos, o que dificulta a comparação. O fato de a probabilidade de passagem para o segundo elo ter sido muito baixa (17%) limitou o número de tentativas em que os participantes tinham a chance de responder no segundo elo do Estudo 2. Consequentemente, o acesso aos reforçadores aconteciam em poucas ocasiões. Os Estudos 3 e 4 envolveram tentativas de escolha entre esquemas concorrentes simples, com manipulação de magnitude e atraso do reforço (Estudo 3) e magnitude e probabilidade do reforço (Estudo 4). Após condições de seleção semelhantes às dos estudos anteriores, os participantes passaram por uma condição com esquemas FR / FR concorrentes (com razão podendo variar de 10 a 80), em que a reversão da preferência foi avaliada. Os dados indicaram que a reversão ocorreu com todos os participantes do Estudo 3 (P7, P8 e P9) com maior preferência do componente com reforço maior atrasado e aconteceu com dois participantes do Estudo 4 (P11 e P12). Esses dados sugerem semelhanças entre o atraso e probabilidade do reforço em esquemas concorrentes simples. Em ambos os Estudos foram conduzidas, posteriormente, condições (CRF, SigFR e FI) em que se avaliou se o padrão de respostas gerado pela condição com FR seria modificado, com maior escolha da outra alternativa com reforço menor imediato (Estudo 3) ou reforço menor e mais provável (Estudo 4). Os dados revelaram que a mudança de padrão ocorreu apenas para dois dos participantes do Estudo 4 (P11 e P12) reforçando relações com os dados de um estudo conduzido anteriormente com pombos

Die vorliegende Dissertation setzt sich damit auseinander, wie das Zusammenspiel von essensbezogener Umwelt und Kognition Ernährungsentscheidungen beeinflusst. Im ersten Manuskript, “When Diets Last: Lower Cognitive Complexity Increases Diet Adherence” wird die Bedeutung der kognitiven Komplexität von Ernährungsregeln für das Einhalten einer Diät untersucht. Können Diäten scheitern, weil sie aus kognitiver Perspektive zu komplex sind, z.B. weil sich Diäthaltende nicht alle wichtigen Informationen merken oder verarbeiten können? 1136 Diäthaltende nahmen an einer längsschnittlichen Onlinestudie teil. Vorangegangenes Diätverhalten, Selbstwirksamkeit, Planung und wahrgenommene Regelschwierigkeit erhöhten das Risiko, die Diät vorzeitig aufzugeben, wobei Selbstwirksamkeit und wahrgenommene Regelschwierigkeit die einflussreichsten Faktoren waren. Im zweiten Manuskript „Meat Label Design: Effects on Stage Progression, Risk Perception, and Product Evaluation” wird der Einfluss gesundheitsrelevanter Information auf Labeln für Produktbewertung und Intention, Tierhaltung und Inhaltsstoffe von Lebensmitteln in die Kaufentscheidung einzubeziehen, untersucht. Es wurde betrachtet, wie Inhalt und Kontext (separate versus conjoint Darbietung) der Labelinformation die Bewertung von Fleischprodukten beeinflusst. Die Ergebnisse zeigen, dass sich bei einer conjoint im Gegensatz zur separaten Darbietung die Bewertung der Produkte umkehrt. Darüber hinaus hatten Personen, die zuvor nicht motiviert waren gesundheitsrelevante Aspekte in ihr Einkaufsverhalten einzubeziehen, nach Betrachten der Label eine höhere Intention diese zu berücksichtigen. Im dritten Manuskript, „Predicting Children’s Meal Preferences: How Much Do Parents Know?“, wurden Präferenzvorhersagen bezüglich der Essensentscheidungen Anderer erforscht. Es wurde untersucht, wie gut und mit Hilfe welcher Information Eltern die Mittagessenpräferenzen ihrer Kinder vorhersagen. Die Vorhersagegenauigkeit der Eltern entsprach der Stabilität der Essenspräferenzen ihrer Kinder, d.h. dass die Eltern so genau waren, wie möglich. Die Ergebnisse suggerieren, dass Eltern vor allem spezifisches Wissen über die Präferenzen ihrer Kinder und Projektion ihrer eigenen Vorlieben für die Vorhersagen nutzten. / This dissertation focuses on food-related decision making, in particular, how food related environments and cognition interact to determine people’s food choices. The first manuscript, “When Diets Last: Lower Cognitive Complexity Increases Diet Adherence,” investigates the role of the cognitive complexity in diet adherence. Can weight loss diets fail because they are too complicated from a cognitive point of view, meaning that dieters are not able to recall or process the diet rules? The impact of excessive cognitive demands on diet adherence were investigated with 1,136 dieters in a longitudinal online-questionnaire. We measured perceived rule complexity controlling for other factors known to influence adherence. Previous diet behavior, self-efficacy, planning and perceived rule complexity predicted an increased risk to quit the diet prematurely, with self-efficacy and diet complexity being the strongest factors. The second manuscript, “Meat Label Design: Effects on Stage Progression, Risk Perception, and Product Evaluation,” presents two studies which tested the impact of health-related meat labels on product evaluation and intention. Specifically, the studies examined how informational content and the context (separate vs. conjoint evaluation) in which labels are assessed influence the evaluation of meat products. The results showed that conjoint assessment of labels can lead to contrary product rankings compared to separate evaluations. Moreover, the results suggest that being exposed to food labels containing specific health-relevant information can increase motivation to consider health aspects in those consumers without previous intention to do so. The third manuscript, “Predicting Children’s Meal Preferences: How Much Do Parents Know?” investigated prediction behavior concerning other people’s food choices. In particular, it asked how accurately and what cues parents use to predict their children’s meal choices. Overall, parents’ prediction accuracy matched the stability of children’s meal choices, implying that accuracy was as high as can be expected. The results suggest parents were able to obtain high predictive accuracy by using specific knowledge about their child’s likes and projecting their own preferences.

Esta tesis utiliza un enfoque experimental para comprender las interacciones dentro de redes y percibir las decisiones causando inversión de preferencia (IP). El Capítulo 1 experimentalmente introduce comunicaciones no vinculantes a un modelo de producción de un bien costoso, que es no excluible entre personas vinculadas en una red. Los resultados muestran que la comunicación de dirección única no mejora coordinación tanto como la comunicación entre conjuntos máximos independientes. El Capítulo 2 analiza experimentalmente un modelo de conflictos bilaterales integrado en redes, donde los oponentes invierten para ganar recursos. Concluye sobre exceso de inversiones comparado a las predicciones de equilibrio. Por último, el Capítulo 3 mira si el efecto dotación inicial resultado de statu quo conduce IP. Esto es analizado por la interrogación de la buena voluntad de cambiar una lotería dotada para otra o pago seguro. En contrario de las predicciones, resultados demuestra que dotaciones son renunciadas con frecuencia. / This thesis uses an experimental approach in understanding group decisions and interactions in networks and perceiving individual decisions causing preference reversal. Chapter 1 experimentally introduces different communication schemes to a production model of a costly good that is non-excludable among individuals linked within a network. Results show that one-way communication is not as efficient as in earlier literature; yet communication among maximal independent sets enhances coordination. Chapter 2 experimentally analyzes a model of multiple bilateral conflicts embedded in networks where opponents invest in conflict technology to win resources. It concludes on tendency to invest in excess of equilibrium predictions. Finally, Chapter 3 looks at whether preference reversal is driven by an endowment effect explanation originating from status quo bias. This is analyzed through questioning individuals' willingness to exchange their endowed lottery for another lottery or sure money. Contrary to the predictions, results show that individuals most often disclaim their endowments.