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We recently reported a study (Warneken & Rosati Proceedings of the Royal Society B, 282, 20150229, ) examining whether chimpanzees possess several cognitive capacities that are critical to engage in cooking. In a subsequent commentary, Beran, Hopper, de Waal, Sayers, and Brosnan Learning & Behavior () asserted that our paper has several flaws. Their commentary (1) critiques some aspects of our methodology and argues that our work does not constitute evidence that chimpanzees can actually cook; (2) claims that these results are old news, as previous work had already demonstrated that chimpanzees possess most or all of these capacities; and, finally, (3) argues that comparative psychological studies of chimpanzees cannot adequately address questions about human evolution, anyway. However, their critique of the premise of our study simply reiterates several points we made in the original paper. To quote ourselves: 'As chimpanzees neither control fire nor cook food in their natural behavior, these experiments therefore focus not on whether chimpanzees can actually cook food, but rather whether they can apply their cognitive skills to novel problems that emulate cooking' (Warneken & Rosati Proceedings of the Royal Society B, 282, 20150229, , p. 2). Furthermore, the methodological issues they raise are standard points about psychological research with animals-many of which were addressed synthetically across our 9 experiments, or else are orthogonal to our claims. Finally, we argue that comparative studies of extant apes (and other nonhuman species) are a powerful and indispensable method for understanding human cognitive evolution. [ABSTRACT FROM AUTHOR]

Humans actively share resources with one another to a much greater degree than do other great apes, and much human sharing is governed by social norms of fairness and equity. When in receipt of a windfall of resources, human children begin showing tendencies towards equitable distribution with others at five to seven years of age. Arguably, however, the primordial situation for human sharing of resources is that which follows cooperative activities such as collaborative foraging, when several individuals must share the spoils of their joint efforts. Here we show that children of around three years of age share with others much more equitably in collaborative activities than they do in either windfall or parallel-work situations. By contrast, one of humans' two nearest primate relatives, chimpanzees (Pan troglodytes), 'share' (make food available to another individual) just as often whether they have collaborated with them or not. This species difference raises the possibility that humans' tendency to distribute resources equitably may have its evolutionary roots in the sharing of spoils after collaborative efforts. [ABSTRACT FROM AUTHOR]

Helping and cooperation are central to human social life. Here, we report two studies investigating these social behaviors in children with autism and children with developmental delay. In the first study, both groups of children helped the experimenter attain her goals. In the second study, both groups of children cooperated with an adult, but fewer children with autism performed the tasks successfully. When the adult stopped interacting at a certain moment, children with autism produced fewer attempts to re-engage her, possibly indicating that they had not formed a shared goal/shared intentions with her. These results are discussed in terms of the prerequisite cognitive and motivational skills and propensities underlying social behavior. [ABSTRACT FROM AUTHOR]

Cooperation among genetically unrelated individuals can be supported by direct reciprocity. Theoretical models and experiments with adults show that the possibility of future interactions with the same partner can promote cooperation via conditionally cooperative strategies such as tit-for-tat (TFT). Here, we introduce a novel implementation of the repeated Prisoner's Dilemma (PD) designed for children to examine whether repeated interactions can successfully promote cooperation in 10 and 11 year olds. We find that children cooperate substantially more in repeated PDs than in one-shot PDs. We also find that girls cooperate more than boys, and that children with more conduct problems cooperate less. Finally, we find that children use conditional cooperation strategies but that these strategies vary by gender and conduct problem rating. Specifically, girls and children with few conduct problems appear to follow an altruistic version of win-stay, lose-shift (WSLS), attempting to re-establish cooperation after they had defected. Boys and children with more conduct problems appear to follow a Grim strategy, defecting for the duration after the partner defects. Thus we provide evidence that children utilize the power of direct reciprocity to promote cooperation in strategic interactions and that, by late elementary school, distinct strategies of conditional cooperation have emerged. [ABSTRACT FROM AUTHOR]

The article provides information on the study which finds that children aged 7 to 8 value equality of resource distribution. The study carried out the experiences of 229 Swiss boys and girls between 3 and 8 years of age. The children in the study were given a choice between two food-allocation options in which they will provide for themselves and/or some for another child. It found that children will not only provide for others, but will also seek an equal distribution, even situations where they could take a larger share for themselves. Moreover, the study shows that the tendency of sharing resources equitably emerges in middle childhood.