Domain-specific inferences about conspecifics' skills by chimpanzees.

Chimpanzees collaborate with conspecifics in their daily life. However, the cognitive processes underlying partner recruitment aren't fully understood. In the current study, chimpanzees needed to recruit a conspecific partner for either a cooperative or competitive experimental task.

Social disappointment and partner presence affect long-tailed macaque refusal behaviour in an 'inequity aversion' experiment.

Protest in response to unequal reward distribution is thought to have played a central role in the evolution of human cooperation. Some animals refuse food and become demotivated when rewarded more poorly than a conspecific, and this has been taken as evidence that non-human animals, like humans, protest in the face of inequity. An alternative explanation-social disappointment-shifts the cause of this discontent away from the unequal reward, to the human experimenter who could-but elects not to-treat the subject well.

Chimpanzees consider freedom of choice in their evaluation of social action.

Judgements of wrongdoing in humans often hinge upon an assessment of whether a perpetrator acted out of free choice: whether they had more than one option. The classic inhibitors of free choice are constraint (e.g.

Reduced risk-seeking in chimpanzees in a zero-outcome game.

A key component of economic decisions is the integration of information about reward outcomes and probabilities in selecting between competing options. In many species, risky choice is influenced by the magnitude of available outcomes, probability of success and the possibility of extreme outcomes. Chimpanzees are generally regarded to be risk-seeking.

Establishing an infrastructure for collaboration in primate cognition research.

Inferring the evolutionary history of cognitive abilities requires large and diverse samples. However, such samples are often beyond the reach of individual researchers or institutions, and studies are often limited to small numbers of species. Consequently, methodological and site-specific-differences across studies can limit comparisons between species.

Competition is crucial for social comparison processes in long-tailed macaques.

Humans modulate their self-evaluations and behaviour as a function of conspecific presence and performance. In this study, we tested for the presence of human-like social comparison effects in long-tailed macaques ( Macaca fascicularis). The monkeys' task was to extract food from an apparatus by pulling drawers within reach and we measured latency between drawer pulls.

The Rationality of (Over)imitation.

Imitation is a powerful and ubiquitous social learning strategy, fundamental for the development of individual skills and cultural traditions. Recent research on the cognitive foundations and development of imitation, though, presents a surprising picture: Although even infants imitate in selective, efficient, and rational ways, children and adults engage in overimitation. Rather than imitating selectively and efficiently, they sometimes faithfully reproduce causally irrelevant actions as much as relevant ones.

Are monkeys intuitive Aristotelians? Associations between target size and vertical target position in long-tailed macaques.

Different hypotheses have been put forward to explain the interaction between size perception and spatial position. To explore the evolutionary roots of these phenomena, we tested long-tailed macaques' performance in a two-choice discrimination task on a touchscreen and contrasted two hypotheses. First, a hierarchy association in which large objects are associated with top positions, due to a link between power, dominance and importance with top position.

Rational over-imitation: Preschoolers consider material costs and copy causally irrelevant actions selectively.

Children's strong tendency to over-imitate - i.e., to reproduce causally irrelevant actions - presents a well-documented, yet puzzling, phenomenon.

Do monkeys compare themselves to others?

Social comparisons are a fundamental characteristic of human behaviour, yet relatively little is known about their evolutionary foundations. Adapting the co-acting paradigm from human research (Seta in J Pers Soc Psychol 42:281-291, 1982. doi: 10.

Over-imitation is not automatic: context sensitivity in children's overimitation and action interpretation of causally irrelevant actions.

Recent research has documented the robust tendency of children to "over-imitate," that is, to copy causally irrelevant action elements in goal-directed action sequences. Different explanations for over-imitation have been proposed. Causal accounts claim that children mistakenly perceive such action elements as causally relevant and, therefore, imitate them.

Why do children overimitate? Normativity is crucial.

Recent research has documented that children readily engage in overimitation, that is, the reproduction of causally irrelevant elements within a bigger action sequence. Different explanations have been put forward. Affiliation accounts claim that children overimitate to affiliate with the model.

Direct and indirect reputation formation in nonhuman great apes (Pan paniscus, Pan troglodytes, Gorilla gorilla, Pongo pygmaeus) and human children (Homo sapiens).

Humans make decisions about when and with whom to cooperate based on their reputations. People either learn about others by direct interaction or by observing third-party interactions or gossip. An important question is whether other animal species, especially our closest living relatives, the nonhuman great apes, also form reputations of others.