O efeito do esforço no valor de uma recompensa

Dissertação de mestrado integrado em Psicologia (área de especialização em Psicologia Experimental e Suas Aplicações)Este estudo teve como objectivo compreender como é que o esforço para obter uma recompensa afecta o seu valor. Na Experiência 1a, seis pombos escolheram entre duas opções, 2s de reforço entregue após um atraso de 20s ou 6s de reforço entregue após um atraso ajustável. Este atraso ajustável aumentava ou diminuía dependendo das escolhas do pombo. Pretendíamos assim ajustar este intervalo para encontrar o ponto de indiferença - duração do atraso com a qual as duas alternativas são igualmente escolhidas. De seguida variou-se o número de bicadas que o pombo tinha que dar para obter os 2s de reforço e verificou-se qual o efeito destas bicadas sobre os pontos de indiferença. Assim, podiam ser exigidas entre 1 e 10 bicadas durante o atraso (fase ‘Taxa Baixa’), entre 10 e 30 bicadas (fase ‘Taxa Intermédia’) ou pelo menos 30 bicadas (fase ‘Taxa Elevada’). Desde modo, com base nos pontos de indiferença, pretendemos verificar se a exigência de respostas durante o atraso leva a escolhas mais impulsivas (da pequena recompensa) ou autocontroladas (da grande recompensa). Os pombos mostraram dificuldade em aprender a tarefa, e por isso o procedimento foi simplificado. Na Experiência 1b o atraso para o reforço de 2s foi diminuído para 10s e houve apenas duas fases. Na fase ‘Taxa Baixa’, durante o atraso de 10s, o pombo não podia dar mais de 5 respostas e na fase ‘Taxa Elevada’ tinha de dar pelo menos 10 respostas. Os resultados mostram que, para a maior parte dos pombos, exigir respostas durante o atraso para uma recompensa, desvaloriza essa recompensa.This study aimed to understand how the effort to obtain a reward affects its value. In Experiment 1a, six pigeons chose between two options, 2s of reinforcer delayed 20s or 6s of reinforcer delivered after an adjustable delay. This adjustable delay increased or decreased depending on the pigeon’s choices. We wanted to adjust this interval to find the indifference point – the delay duration at which the two alternatives are equally chosen. We then varied the number of pecks required for the 2-s food and assessed how these pecks affected the indifference points. Thus, it could be required between 1 and 10 pecks during the delay (phase ‘Low Rate’), between 10 and 30 pecks (phase ‘Intermediate Rate’) or at least 30 pecks (phase ‘High Rate’). Based on the indifference points, we assessed whether requiring responses during the delay led to more impulsive (small reward) or self-controlled (large reward) choices. The pigeons showed difficulties learning the task, so the procedure was simplified. In Experiment 1b the 2-s reinforcer delay was reduced to 10s and there were only two phases. In the phase ‘Low Rate’ during the 10-s delay the pigeon could not give more than 5 phase responses and in phase ‘High Rate’ it had to give at least 10 responses. The results showed that, for most of the pigeons, requiring pecks during the delay devalues the reward

The perspective of cyclists on current practices with digital tools and envisioned services for urban cycling

This is a preprint version of an accepted manuscript in WorldCist'21 -9th World Conference on Information Systems and TechnologiesAs cycling becomes increasingly important in sustainable mobility policies, there is also an urge for new digital applications and services for urban cycling. This new generation of cycling applications should be able to connect cyclists with their local cycling ecosystem, promote cycling, and empower cyclists to become active agents of urban mobility. In this work, we aim to explore the new opportunity space of digital tools and applications designed specifically for urban cycling. We pursue this goal by trying to uncover current practices associated with digital tools that are already available and also by trying to uncover new information needs, even those that cyclists are not yet able to fully express. To explore these topics, we conducted 2 focus group sessions and 10 interviews with cyclists. The result is a set of design opportunities for the development of new applications, tools and methods for improving the cycling experience in the context of urban mobility. We expect this contribution might help to better define the design space of innovative digital tools for urban cyclists.This work is supported by: European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) [Project nº 039334; Funding Reference: POCI-01-0247- FEDER-039334

Enhancing the motorcycling experience with social applications: A study of user needs

a preprint versionFor many riders, the motorcycle is much more than a transportation mode. Riding a motorcycle can be a pleasurable experience in itself, and the mo-torcycle is frequently a tool of socialization. An evidence for that can be found in the numerous motorcycling communities around the world. However, those communities may not be accessible to everyone, or they may not satisfy every-one. We believe that a social application for motorcyclists could reach more rid-ers and has the potential of more easily fitting their needs. To explore this idea, we conducted focus groups with motorcyclists, exploring their current practices in digital tools as well as their needs and desires that could possibly be integrated in a social application. The results hinted on several aspects that need to be con-sidered in the design of a social application for motorcyclists. Generally, motor-cyclists are willing to receive and share information with others, and referred several needs in terms of communication and trip planning. However, they also showed concerns regarding a digital tool associated with riding, both for safety reasons and because it could disrupt the riding experience. We conclude that not only the needs but also the concerns must be considered in the design of this new digital tool.This work is supported by: European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) [Project nº 039334; Funding Reference: POCI-01-0247-FEDER-039334]

A comprehensive assessment of the transcriptome of cork oak (Quercus suber) through EST sequencing

Background: Cork oak (Quercus suber) is one of the rare trees with the ability to produce cork, a material widely used to make wine bottle stoppers, flooring and insulation materials, among many other uses. The molecular mechanisms of cork formation are still poorly understood, in great part due to the difficulty in studying a species with a long life-cycle and for which there is scarce molecular/genomic information. Cork oak forests are of great ecological importance and represent a major economic and social resource in Southern Europe and Northern Africa. However, global warming is threatening the cork oak forests by imposing thermal, hydric and many types of novel biotic stresses. Despite the economic and social value of the Q. suber species, few genomic resources have been developed, useful for biotechnological applications and improved forest management. Results: We generated in excess of 7 million sequence reads, by pyrosequencing 21 normalized cDNA libraries derived from multiple Q. suber tissues and organs, developmental stages and physiological conditions. We deployed a stringent sequence processing and assembly pipeline that resulted in the identification of ~159,000 unigenes. These were annotated according to their similarity to known plant genes, to known Interpro domains, GO classes and E.C. numbers. The phylogenetic extent of this ESTs set was investigated, and we found that cork oak revealed a significant new gene space that is not covered by other model species or EST sequencing projects. The raw data, as well as the full annotated assembly, are now available to the community in a dedicated web portal at http://www.corkoakdb.org. Conclusions: This genomic resource represents the first trancriptome study in a cork producing species. It can be explored to develop new tools and approaches to understand stress responses and developmental processes in forest trees, as well as the molecular cascades underlying cork differentiation and disease response.Peer Reviewe

Escolhas subótimas e o valor da informação

Tese de Doutoramento em Psicologia Básica.The environment is full of unpredictable events. Information that reduces uncertainty about events allows an organism to better predict and prepare to what is to come. For that reason, obtaining information can be crucial for survival. In the present dissertation we explored a task in which animals trade food for information. In this task, animals choose between two options: the Informative Option delivers food on 20% of the trials after a 10-s delay, signaled by “good-news stimulus”, and delivers no food on the remaining 80% of the trials, signaled by a “bad-news stimulus”. The Non-informative Option delivers food after 10 s on 50% of the trials, regardless of which of two different stimulus is shown. A consistent and almost exclusive preference for the Informative Option has been found, even though that results in loss of food. In Study 1 we showed that this suboptimal choice can be explained by animals ignoring the bad-news stimulus: its probability and duration had little to no effect on preference. In Study 2 we showed that, when given the opportunity, animals escape from the bad-news stimulus. Moreover, our results suggest that ignoring the bad-news stimulus means that, even though this stimulus is perceived, it is not associated with the choice of the Informative Option. In Study 3 we increased the probability of reinforcement following the until-then bad-news stimulus, and found that, as paradoxically as it may seem, within the tested range, the value of the Informative Option decreased as the probability of reinforcement increased. This increase in reinforcement was consistent with an increase in the association of the bad-news stimulus to the Informative Option. In all studies we showed that an optimal foraging-based model (Vasconcelos, Monteiro, & Kacelnik, 2015) accounted at least as well as a conditioned reinforcement-based model (Mazur, 1987), thus deconstructing the idea that this suboptimal behavior contradicts optimal foraging principles. These findings are expected to contribute in calling attention to the ecology of the animal, bringing animal psychology and behavior ecology closer.O meio ambiente é repleto de eventos imprevisíveis. A informação que reduz a incerteza acerca dos eventos permite um organismo prever e preparar-se melhor para o futuro. Por essa razão, obter informação pode ser crucial para a sobrevivência. Nesta dissertação explorámos uma tarefa na qual os animais trocam comida por informação. Nesta tarefa, os animais escolhem entre duas opções: a Opção Informativa dá comida em 20% dos ensaios após um atraso de 10 s, sinalizados por um “estímulo de boas notícias”, e não dá comida nos restantes 80% dos ensaios, sinalizados por um “estímulo de más notícias”. A Opção Não Informativa dá comida após 10 s em 50% dos ensaios, independentemente de qual de dois estímulos é apresentado. Tem-se encontrado uma preferência consistente e praticamente exclusiva pela Opção Informativa, apesar disso resultar em perda de comida. No Estudo 1 mostrámos que esta escolha subótima pode ser explicada pelos animais ignorarem o estímulo das más notícias: a sua probabilidade e duração tiveram pouco ou nenhum efeito na preferência. No Estudo 2 mostrámos que, quando dada a oportunidade, os animais escapam do estímulo das más notícias. Para além disso, os nossos resultados sugerem que ignorar o estímulo das más notícias significa que, apesar de este estímulo ser percecionado, não é associado com a escolha da Opção Informativa. No Estudo 3 aumentámos a probabilidade de reforço após o até então estímulo das más notícias e descobrimos que, paradoxalmente, dentro da amplitude testada, o valor da Opção Informativa diminuiu à medida que a probabilidade de reforço aumentou. Este aumento foi consistente com um aumento na associação do estímulo das más notícias com a Opção Informativa. Em todos os estudos mostrámos que um modelo baseado na em optimal foraging (Vasconcelos, Monteiro, & Kacelnik, 2015) dá conta dos dados tanto quanto um modelo baseado em reforçamento condicionado (Mazur, 1987), desconstruindo assim a ideia de que este comportamento subótimo contradiz os princípios de optimal foraging. Esperamos que estes resultados contribuam para chamar à atenção a ecologia do animal, unindo assim a psicologia animal e a ecologia comportamental

Modelo conjunto multivariado para dados longitudinais: um estudo de simulação

Dissertação de mestrado em EstatísticaOs modelos conjuntos de dados longitudinais e de tempo até ao evento são comuns na análise de dados quando existe uma associação entre (1) uma variável observada longitudinalmente e (2) uma variável que mede o tempo até à ocorrência de um evento específico. Dada a utilidade destes modelos, há actualmente pelo menos duas implementações de bibliotecas disponíveis em R: joineR e JM. No entanto, estes modelos são complexos porque incluem frequentemente efeitos aleatórios partilhados entre os sub-modelos longitudinal e tempo até ao evento. Como consequência, a implementação destes modelos conjuntos é computacionalmente exigente. Neste estudo exploramos o Modelo Gaussiano Transformado, um modelo totalmente paramétrico, onde se assume que a distribuição conjunta dos dados longitudinais e dos dados transformados de tempo até ao evento segue uma distribuição normal multivariada. Para tornar o modelo fácil de implementar e com parâmetros intuitivos de compreender, apresentamos uma metodologia em que os modelos conjuntos multivariados mistos são ajustados utilizando a biblioteca lme do R. Para isso, propomos oito estruturas para o Modelo Gaussiano Transformado, e num estudo de simulação testamos quatro desses modelos. Verificámos que, em geral, estes modelos forneceram boas estimativas dos parâmetros, especialmente quando a variabilidade entre sujeitos é elevada e os erros de medição são pequenos. Verificámos também que o Modelo Gaussiano Transformado pode assumir estruturas complexas apesar de ser computacionalmente menos exigente do que as alternativas. Acreditamos que pode ser utilizado para análise exploratória, por exemplo para seleccionar as variáveis explicativas mais influentes. No final, discutimos as diferentes vantagens e desvantagens de cada um dos cinco modelos testados.Joint models for longitudinal and time-to-event data are common in data analysis when there is an association between (1) a longitudinally observed variable and (2) a variable measuring the time until the occurrence of a specific event. Given the usefulness of these models, there are currently at least two available package implementations in R: joineR and JM. However, these models are complex because they often include shared-random effects between the longitudinal and time-to-event sub-models. As a con sequence, implementation of these joint models is computationally demanding. In this study we explore the Transformed Gaussian Model, a fully parametric model, where the joint distribution of longitudinal and transformed time-to-event data are assumed to follow a multivariate normal distribution. To make the model easy to implement and with meaningful parameters, we present a methodology where multivariate mixed joint models are fitted using the R package lme. For that, we propose eight structures for the Transformed Gaussian Model, and in a simulation study we test four of those models. We found that, in general, these models provided good estimates of the parameters, specially when the between-subject variability is high and the measurement errors are small. Also, we found that the Transformed Gaussian Model can assume complex structures despite the fact of being computationally less demanding than the alternatives. We believe it can be used for exploratory analysis, for instance to select the more influencing explanatory variables. At the end, we discuss the different advantages and disadvantages of each of the five tested models

Testing the Boundaries of "Paradoxical" Predictions: Pigeons Do Disregard Bad News

Several studies have shown that, when offered a choice between an option followed by stimuli indicating whether or not reward is forthcoming and an option followed by noninformative stimuli, animals strongly prefer the former even when the latter is more profitable. Though this paradoxical preference appears to question the principles of optimal foraging theory, Vasconcelos, Monteiro, and Kacelnik (2015) proposed an optimality model that shows how such preference maximizes gains under certain conditions. In this paper, we tested the model's core assumption that a stimulus signaling the absence of food should not influence choice independently of its other properties, such as probability or duration. In 2 experiments, pigeons chose between 2 options: the "informative option" delivered food on 20% of the trials after a 10-s delay, signaled by a "good-news" stimulus, and delivered no food on the remaining 80% of the trials, signaled by a "bad-news" stimulus. The "noninformative option" delivered food after 10 s on 50% of the trials, regardless of the signal shown. In Experiment 1, the probability of the bad-news stimulus was manipulated from 0.80 to 1.00; in Experiment 2, the duration of the bad-news stimulus was increased every time pigeons preferred the informative option, reaching at least 200 s. Consistent with the model's predictions, pigeons clearly preferred the informative option even when the noninformative option delivered 9 (Experiment 1) and 35 (Experiment 2) times more food.- This study was conducted at the Psychology Research Centre, University of Minho, Portugal, and was supported by the Portuguese Foundation for Science and Technology (FCT) and the Portuguese Ministry of Education and Science through national funds cofinanced by FEDER under the PT2020 Partnership Agreement (Grant UID/PSI/01662/2013). This work was also supported by FCT Grant PTDC/MHC-PCN/3540/2012 to Armando Machado. Ines Fortes and Marco Vasconcelos were supported by an FCT Doctoral Grant SFRH/BD/77061/2011 and an FCT Investigator Grant IF/01624/2013, respectively. We are grateful to Thomas Zentall and the members of the Animal Learning and Behavior Laboratory of University of Minho for their helpful comments on a prior version of this paper.info:eu-repo/semantics/publishedVersio

Do pigeons (columba livia) use information about the absence of food appropriately?: a further look into suboptimal choice

In the natural environment, when an animal encounters a stimulus that signals the absence of food-a 'bad-news' stimulus-it will most likely redirect its search to another patch or prey. Because the animal does not pay the opportunity cost of waiting in the presence of a bad-news stimulus, the properties of the stimulus (e.g., its duration and probability) may have little impact in the evolution of the decision processes deployed in these circumstances. Hence, in the laboratory, when animals are forced to experience a bad-news stimulus they seem to ignore its duration, even though they pay the cost of waiting. Under certain circumstances, this insensitivity to the opportunity cost can lead to suboptimal preferences, such as a preference for an option yielding a low rather than a high rate of reinforcement. In 2 experiments, we tested Vasconcelos, Monteiro, and Kacelnik's (2015) assumption that, if given the opportunity, animals will escape the bad-news stimulus. To predict when an escape response should occur, we incorporated ideas from the prey choice model into Vasconcelos et al. (2015) model and made 2 novel predictions. Namely, both longer intertrial intervals and longer durations of signals predicting food or no food should lead to higher proportions of escape responses. The results of 2 experiments with pigeons supported these predictions.This study was conducted at the Psychology Research Centre, University of Minho, Portugal, and was supported by the Portuguese Foundation for Science and Technology (FCT) and the Portuguese Ministry of Education and Science through national funds cofinanced by FEDER under the PT2020 Partnership Agreement (UID/PSI/01662/2013). This work was also supported by FCT Grant PTDC/MHC-PCN/3540/2012 to Armando Machado. Ines Fortes was supported by FCT Doctoral Grant (SFRH/BD/77061/2011). We thank the members of the Animal Learning and Behavior Laboratory of University of Minho for their comments on a prior version of this paper.info:eu-repo/semantics/publishedVersio

The effect of response rate on reward value in a self-control task

To understand how effort, defined by number of responses required to obtain a reward, affects reward value, five pigeons were exposed to a self-control task. They chose between two alternatives, 2s of access to food after a delay of 10s, and 6s of access to food after an adjusting delay. The adjusting delay increased or decreased depending on the pigeons' choices. The delay at which the two alternatives were equally chosen defined the indifference point. To determine whether requiring responses during the delay led to more impulsive (smaller-sooner rewards) or self-controlled (larger-later rewards) choices, we varied the number of required pecks during the 10-s delay to the 2-s reinforcer, and assessed how the requirement affected the indifference points. In the High Rate Phase, they had to peck at least 10 times during the delay; in the Low Rate Phase, they could peck at most 5 times during the delay. For four pigeons the indifference point increased with the response requirement; for one pigeon it decreased. The results suggest that, in general, reward value varies inversely with effort.This work was supported by the Portuguese Foundation for Science and Technology (FCT) Grant (PTDC/MHC-PCN/3540/2012) to Armando Machado and Marco Vasconcelos. Ines Fortes and Marco Vasconcelos were supported by an FCT Doctoral Grant (SFRH/BD/77061/2011) and an FCT Investigator Grant (IF/01624/2013), respectively. We are grateful to the members of the Animal Learning and Behavior Laboratory of University of Minho for their helpful comments on a prior version of this paper.info:eu-repo/semantics/publishedVersio

The paradoxical effect of low reward probabilities in suboptimal choice

When offered a choice between 2 alternatives, animals sometimes prefer the option yielding less food. For instance, pigeons and starlings prefer an option that on 20% of the trials presents a stimulus always followed by food, and on the remaining 80% of the trials presents a stimulus never followed by food (the Informative Option), over an option that provides food on 50% of the trials regardless of the stimulus presented (the Noninformative Option). To explain this suboptimal behavior, it has been hypothesized that animals ignore (or do not engage with) the stimulus that is never followed by food in the Informative Option. To assess when pigeons attend to the stimulus usually not followed by food, we increased the probability of reinforcement, p, in the presence of that stimulus. Across 2 experiments, we found that the value of the Informative Option decreased with p. To account for the results, we added to the Reinforcement Rate Model (and also to the Hyperbolic Discounting Model) an engagement function, f(p), that specified the likelihood the animal attends to a stimulus followed by reward with probability p, and then derived the model predictions for 2 forms of f(p), a linear function, and an all-or-none threshold function. Both models predicted the observed findings with a linear engagement function: The higher the probability of reinforcement after a stimulus, the higher the probability of engaging the stimulus, and, surprisingly, the less the value of the option comprising the stimulus.This study was conducted at the Psychology Research Centre (UID/PSI/01662/2013) of the University of Minho, and supported by the Portuguese Foundation for Science and Technology (FCT) and the Portuguese Ministry of Science, Technology and Higher Education through national funds and cofinanced by FEDER through COMPETE2020 under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007653). This work was also supported by an FCT Grant (PTDC/MHC-PCN/3540/2012) to AM. IF and CP were supported by FCT Doctoral Grants (SFRH/BD/77061/2011 and SFRH/BD/78566/2011, respectively)