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Full-Text Articles in Psychology
Evolutionary Pressures On Primate Intertemporal Choice, Jeffrey R. Stevens
Evolutionary Pressures On Primate Intertemporal Choice, Jeffrey R. Stevens
Department of Psychology: Faculty Publications
From finding food to choosing mates, animals must make intertemporal choices that involve fitness benefits available at different times. Species vary dramatically in their willingness to wait for delayed rewards. Why does this variation across species exist? An adaptive approach to intertemporal choice suggests that time preferences should reflect the temporal problems faced in a species' environment. Here, I use phylogenetic regression to test whether allometric factors (relating to body size), relative brain size, and social group size predict how long 13 primate species will wait in laboratory intertemporal choice tasks. Controlling for phylogeny, a composite allometric factor that includes …
Wild Justice Redux: What We Know About Social Justice In Animals And Why It Matters, Jessica Pierce, Marc Bekoff
Wild Justice Redux: What We Know About Social Justice In Animals And Why It Matters, Jessica Pierce, Marc Bekoff
Ethology Collection
Social justice in animals is beginning to attract interest in a broad range of academic disciplines. Justice is an important area of study because it may help explain social dynamics among individuals living in tightly- knit groups, as well as social interactions among individuals who only occasionally meet. In this paper, we provide an overview of what is currently known about social justice in animals and offer an agenda for further research. We provide working definitions of key terms, outline some central research questions, and explore some of the challenges of studying social justice in animals, as well as the …
The Selfish Nature Of Generosity: Harassment And Food Sharing In Primates, Jeffrey R. Stevens
The Selfish Nature Of Generosity: Harassment And Food Sharing In Primates, Jeffrey R. Stevens
Jeffrey Stevens Publications
Animals may share food to gain immediate or delayed fitness benefits. Previous studies of sharing have concentrated on delayed benefits such as reciprocity, trade and punishment. This study tests an alternative model (the harassment or sharing–under–pressure hypothesis) in which a food owner immediately benefits because sharing avoids costly harassment from a beggar. I present an experiment that varies the potential ability of the beggar to harass, and of the owner to defend the food, to examine the effects of harassment on food sharing in two primate species: chimpanzees (Pan troglodytes) and squirrel monkeys (Saimiri boliviensis). For …