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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).

The temporal bisection task, one of the most widely used to study time perception, has helped to understand the psychophysics of time and the mechanisms of timing across different species. We extended the temporal bisection task to dogs. Five dogs were reinforced for choosing a yellow but not a blue stimulus after a 1-s tone, and for choosing a blue but not a yellow stimulus after a 4-s tone. After they learned this conditional discrimination, the dogs chose between the blue and yellow stimuli after tones with intermediate durations (1.4, 2.0, and 2.8 s). The results showed that the proportion of “Long” choices increased monotonically with stimulus duration. Moreover, the point of subjective equality was slightly below the geometric mean of the trained tone durations. These psychophysical results are consistent with those obtained with other nonhuman species, and suggest that common mechanisms underlie timing across different mammals and birds., This research was part of the scientific program of Instituto Nacional de Ciência e Tecnologia Sobre Comportamento, Cognição e Ensino, with support from the Brazilian National Research Council (CNPq, Grant 465686/2014-1) and the São Paulo Research Foundation (Grant 2014/50909-8). Camila Domeniconi had a postdoctoral fellowship from the Foundation for Research Support in the State of São Paulo (FAPESP, 2009/ 18479-5). She has a research productivity fellowship bythe National Council for Scientific and Technological Development (CNPq, 301623/2012-0). Armando Machado was supported by grant PTDC/MHC-PCN/ 3540/ 2012 from the Portuguese Foundation for Science and Technology., info:eu-repo/semantics/publishedVersion

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/publishedVersion

We examined whether temporal learning in a bisection task is absolute or relational. Eight pigeons learned to choose a red key after a t-seconds sample and a green key after a 3t-seconds sample. To determine whether they had learned a relative mapping (short -> Red, long -> Green) or an absolute mapping (t-seconds -> Red, 3t-seconds -> Green), the pigeons then learned a series of new discriminations in which either the relative or the absolute mapping was maintained. Results showed that the generalization gradient obtained at the end of a discrimination predicted the pattern of choices made during the first session of a new discrimination. Moreover, most acquisition curves and generalization gradients were consistent with the predictions of the learning-to-time model, a Spencean model that instantiates absolute learning with temporal generalization. In the bisection task, the basis of temporal discrimination seems to be absolute, not relational., The authors were supported by grants from the Portuguese Foundation for Science and Technology (FCT SFRH/BD/73875/2010 and PTDC/MHC-PCN/3540/2012). The study was conducted at the Psychology Research Centre of the University of Minho, and was partially supported by the Portuguese Foundation for Science and Technology and the Portuguese Ministry of Education and Science through national funds and cofinanced by FEDER under the PT2020 Partnership Agreement (UID/PSI/01662/2013). The authors thank Catarina Soares and Margarida Monteiro for helping with data collection, and the members of the Animal Learning and Behavior Lab for comments on a first version of the manuscript. Results reported here were presented at the 26th Meeting of the Spanish Society for Comparative Psychology, Braga, Portugal, and at the 2014 Annual Symposium of the Society for the Quantitative Analysis of Behavior, Chicago, Illinois., info:eu-repo/semantics/publishedVersion

Within the complex set of activities that comprise the scientific method, three clusters of activities can be recognized: experimentation, mathematization, and conceptual analysis. In psychology, the first two of these clusters are well-known and valued, but the third seems less known and valued. The authors show the value of these three clusters of scientific method activities in the works of the quintessential scientist Galileo Galilei. They then illustrate how conceptual analysis can be used in psychology to clarify the grammar and meaning of concepts, expose conceptual problems in models, reveal unacknowledged assumptions and steps in arguments, and evaluate the consistency of theoretical accounts. The article concludes with a discussion of three criticisms of conceptual analysis., Armando Machado was funded by a grant from the Portuguese Foundation for Science and Technology. We thank Susan Goldstein for sharing her expertise about construct validity, info:eu-repo/semantics/publishedVersion