Preference Transitivity and Symbolic Representation in Capuchin Monkeys (Cebus apella)

BACKGROUND: Can non-human animals comprehend and employ symbols? The most convincing empirical evidence comes from language-trained apes, but little is known about this ability in monkeys. Tokens can be regarded as symbols since they are inherently non-valuable objects that acquire an arbitrarily assigned value upon exchange with an experimenter. Recent evidence suggested that capuchin monkeys, which diverged from the human lineage 35 million years ago, can estimate, represent and combine token quantities. A fundamental and open question is whether monkeys can reason about symbols in ways similar to how they reason about real objects. METHODOLOGY/PRINCIPAL FINDINGS: Here we examined this broad question in the context of economic choice behavior. Specifically, we assessed whether, in a symbolic context, capuchins' preferences satisfy transitivity--a fundamental trait of rational decision-making. Given three options A, B and C, transitivity holds true if A > or = B, B > or = C and A > or = C (where > or = indicates preference). In this study, we trained monkeys to exchange three types of tokens for three different foods. We then compared choices monkeys made between different types of tokens with choices monkeys made between the foods. Qualitatively, capuchins' preferences revealed by the way of tokens were similar to those measured with the actual foods. In particular, when choosing between tokens, monkeys displayed strict economic preferences and their choices satisfied transitivity. Quantitatively, however, values measured by the way of tokens differed systematically from those measured with the actual foods. In particular, for any pair of foods, the relative value of the preferred food increased when monkeys chose between the corresponding tokens. CONCLUSIONS/SIGNIFICANCE: These results indicate that indeed capuchins are capable of treating tokens as symbols. However, as they do so, capuchins experience the cognitive burdens imposed by symbolic representation

Development of a Dog-Assisted Activity Program in an Elementary Classroom

Here we describe a pilot Dog-Assisted Activity program that was designed to improve wellbeing and social integration in a multi-cultural elementary classroom in which some episodes of bullying had been reported. We developed a 5-encounters protocol with the aim of introducing pet dogs into the class to stimulate understanding of different types of communication and behavior, ultimately facilitating positive relationships among peers. A preliminary evaluation was carried out in order to assess the effect of the program on teachers’ perception of children’s difficulties (e.g., peer relationship problems) and strengths (prosocial behaviors) by means of a brief behavioral screening tool, the Strengths and Difficulties Questionnaire (SDQ—Teacher version). Overall results indicate that, by means of the recognition of the dogs’ behavior and non-verbal communication, children were able to express their emotions and to show behaviors that had not been recognized by the teachers prior to the intervention. In particular, the SDQ Total Difficulties scores suggest that the teacher had increased awareness of the students’ difficulties as a result of the dog-assisted program. Overall, the presence of animals in the educational environment may provide enjoyment and hands-on educational experiences, enhanced psychological wellbeing, and increased empathy and socio-emotional development