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.

Functional fixedness in chimpanzees.

Differences in the tool use of non-human primates and humans are subject of ongoing debate. In humans, representations of object functions underpin efficient tool use. Yet, representations of object functions can lead to functional fixedness, which describes the fixation on a familiar tool function leading to less efficient problem solving when the problem requires using the tool for a new function.

How can I find what I want? Can children, chimpanzees and capuchin monkeys form abstract representations to guide their behavior in a sampling task?

concepts are a powerful tool for making wide-ranging predictions in new situations based on little experience. Whereas looking-time studies suggest an early emergence of this ability in human infancy, other paradigms like the relational match to sample task often fail to detect abstract concepts until late preschool years. Similarly, non-human animals show difficulties and often succeed only after long training regimes.

Chimpanzees prepare for alternative possible outcomes.

When facing uncertainty, humans often build mental models of alternative outcomes. Considering diverging scenarios allows agents to respond adaptively to different actual worlds by developing contingency plans (covering one's bases). In a pre-registered experiment, we tested whether chimpanzees () prepare for two mutually exclusive possibilities.

Chimpanzee and Human Risk Preferences Show Key Similarities.

Risk preference impacts how people make key life decisions related to health, wealth, and well-being. Systematic variations in risk-taking behavior can be the result of differences in fitness expectations, as predicted by life-history theory. Yet the evolutionary roots of human risk-taking behavior remain poorly understood.

Do chimpanzees reason logically?

Psychologists disagree about the development of logical concepts such as or and not. While some theorists argue that infants reason logically, others maintain that logical inference is contingent on linguistic abilities and emerges around age 4. In this Registered Report, we conducted five experiments on logical reasoning in chimpanzees.

The structure of executive functions in preschool children and chimpanzees.

Executive functions (EF) are a core aspect of cognition. Research with adult humans has produced evidence for unity and diversity in the structure of EF. Studies with preschoolers favour a 1-factor model, in which variation in EF tasks is best explained by a single underlying trait on which all EF tasks load.

How children revise their beliefs in light of reasons.

We investigate how the ability to respond appropriately to reasons provided in discourse develops in young children. In Study 1 (N = 58, Germany, 26 girls), 4- and 5-, but not 3-year-old children, differentiated good from bad reasons. In Study 2 (N = 131, Germany, 64 girls), 4- and 5-year-old children considered both the strength of evidence for their initial belief and the quality of socially provided reasons for an alternative view when deciding whether to change their minds.

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.

Evidence for a developmental shift in the motivation underlying helping in early childhood.

We investigated children's positive emotions as an indicator of their underlying prosocial motivation. In Study 1, 2-, and 5-year-old children (N = 64) could either help an individual or watch as another person provided help. Following the helping event and using depth sensor imaging, we measured children's positive emotions through changes in postural elevation.

Children across societies enforce conventional norms but in culturally variable ways.

Individuals in all societies conform to their cultural group's conventional norms, from how to dress on certain occasions to how to play certain games. It is an open question, however, whether individuals in all societies actively enforce the group's conventional norms when others break them. We investigated third-party enforcement of conventional norms in 5- to 8-y-old children ( = 376) from eight diverse small-scale and large-scale societies.

Chimpanzees consider alternative possibilities.

Humans reason not only about actual events (what is), but also about possible events (what could be). Many key operations of human cognition involve the representation of possibilities, including moral judgment, future planning, and causal understanding. But little is known about the evolutionary roots of this kind of thought.

The influence of friendship and merit on children's resource allocation in three societies.

Recent work has suggested that principles of fairness that seem like natural laws to the Western mind, such as sharing more of the spoils with those who contributed more, can in fact vary significantly across populations. To build a better understanding of the developmental roots of population differences with respect to fairness, we investigated whether 7-year-old children (N = 432) from three cultural backgrounds-Kenya, China, and Germany-consider friendship and merit in their distribution of resources and how they resolve conflicts between the two. We found that friendship had considerable and consistent influence as a cross-culturally recurrent motivation: children in all three cultures preferentially shared with a friend rather than with a neutral familiar peer.

Ravens parallel great apes in physical and social cognitive skills.

Human children show unique cognitive skills for dealing with the social world but their cognitive performance is paralleled by great apes in many tasks dealing with the physical world. Recent studies suggested that members of a songbird family-corvids-also evolved complex cognitive skills but a detailed understanding of the full scope of their cognition was, until now, not existent. Furthermore, relatively little is known about their cognitive development.

Children Delay Gratification for Cooperative Ends.

To cooperate effectively, both in small-scale interactions and large-scale collective-action problems, people frequently have to delay gratification (i.e., resist short-term temptations in favor of joint long-term goals).

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.

Innovative problem solving in great apes: the role of visual feedback in the floating peanut task.

Nonhuman great apes show remarkable behavioural flexibility. Some individuals are even able to use water as a tool: They spit water into a vertical tube to make a peanut float upwards until it comes into reach (floating peanut task; FPT). In the current study, we used the FPT to investigate how visual feedback, an end-state demonstration and a social demonstration affect task performance in nonhuman great apes in three experiments.

Chimpanzees monopolize and children take turns in a limited resource problem.

Competition over scarce resources is common across the animal kingdom. Here we investigate the strategies of chimpanzees and children in a limited resource problem. Both species were presented with a tug-of-war apparatus in which each individual in a dyad received a tool to access a reward, but tools could not be used simultaneously.

Publisher Correction: An investigation of children's strategies for overcoming the tragedy of the commons.

In the version of this Article originally published, two notes reading '[CJ1]' and '[CJ1]This should stay the same. It does refer to a particular seminal experiment and is also not the subject of the citation (40) which refers to a review article' were mistakenly left in the seventh paragraph of the text. These notes have now been removed.

Human children but not chimpanzees make irrational decisions driven by social comparison.

Human evolutionary success is often argued to be rooted in specialized social skills and motivations that result in more prosocial, rational and cooperative decisions. One manifestation of human ultra-sociality is the tendency to engage in social comparison. While social comparison studies typically focus on cooperative behaviour and emphasize concern for fairness and equality, here we investigate the competitive dimension of social comparison: a preference for getting more than others, expressed in a willingness to maximize relative payoff at the cost of absolute payoff.

An investigation of children's strategies for overcoming the tragedy of the commons.

Common-pool resource (CPR) dilemmas are pervasive challenges to overcome. We presented six-year-old children with an experimental CPR paradigm involving a renewable water resource, which children could collect to win individual rewards. To maximize water collection, children had to wait for water to accumulate, without collapsing the resource.

The Development of Prosocial Attention Across Two Cultures.

Despite the significance of prosocial attention for understanding variability in children's prosociality little is known about its expression beyond infancy and outside the Western cultural context. In the current study we asked whether children's sensitivity to others' needs varies across ages and between a Western and Non-Western cultural group. We carried out a cross-cultural and cross-sectional eye tracking study in Kenya ( = 128) and Germany ( = 83) with children between the ages of 3 to 9 years old.

Children engage in competitive altruism.

Humans cultivate their reputations as good cooperators, sometimes even competing with group mates, to appear most cooperative to individuals during the process of selecting partners. To investigate the ontogenetic origins of such "competitive altruism," we presented 5- and 8-year-old children with a dyadic sharing game in which both children simultaneously decided how many rewards to share with each other. The children were either observed by a third-person peer or not.

Young children's reputational strategies in a peer group context.

Reputational concerns are known to promote cooperation. Individuals regularly act more prosocially when their behavior is observable by others. Here, we investigate 4- and 5-year-old (N = 144) children's reputational strategies in a competitive group setting.