From what I want to do to what we decided to do: 5-year-olds, but not 3-year-olds, honor their agreements with peers.

Sometimes we have a personal preference but we agree with others to follow a different course of action. In this study, 3- and 5-year-old children (N = 160) expressed a preference for playing a game one way and were then confronted with peers who expressed a different preference. The experimenter then either got the participants to agree with the peers explicitly or just shrugged her shoulders and moved on. The children were then left alone to play the game unobserved. Only the older children stuck to their agreement to play the game as the peers wished. These results suggest that by 5 years of age children's sense of commitment to agreements is strong enough to override their personal preferences.

Preschoolers consider (absent) others when choosing a distribution procedure.

This study investigated how the presence of others and anticipated distributions for self influence children's fairness-related decisions in two different socio-moral contexts. In the first part, three- and five-year-old children (N = 120) decided between a fair and an unfair wheel of fortune to allocate resources (procedural justice). In the second part, they directly chose between two distributions of resources (distributive justice). While making a decision, each child was either observed by the affected group members (public), alone (private), or no others were introduced (non-social control). Children choose the fair option more often when others were affected (independently of their presence) only in the procedural justice task. These results suggest that using a fair procedure to distribute resources allows young preschoolers to overcome selfish tendencies.

The influence of intention and outcome on young children's reciprocal sharing.

This study investigated the influence of underlying intentions and outcomes of a partner's sharing behavior on young children's reciprocity. We provided 3- and 5-year-old children with the opportunity to share with a partner following different treatments of a partner's intention (to share or not to share) that led to different outcomes (children got or did not get stickers from their partner). For the 3-year-olds, we found that the outcome of the previous interaction influenced how much they shared, whereas the intention of their partner affected how readily they initiated sharing in response to social cues. For the 5-year-olds, we found that both outcome and intention affected how much they shared as well as how readily they initiated sharing. This suggests that already 3-year-olds are able to take into account outcome and intention information separately in reciprocal sharing. However, only 5-year-olds can combine both to flexibly maintain social interactions without running the risk of being exploited by others.

Young children are more willing to accept group decisions in which they have had a voice.

People accept an unequal distribution of resources if they judge that the decision-making process was fair. In this study, 3- and 5-year-old children played an allocation game with two puppets. The puppets decided against a fair distribution in all conditions, but they allowed children to have various degrees of participation in the decision-making process. Children of both ages protested less when they were first asked to agree with the puppets' decision compared with when there was no agreement. When ignored, the younger children protested less than the older children-perhaps because they did not expect to have a say in the process-whereas they protested more when they were given an opportunity to voice their opinion-perhaps because their stated opinion was ignored. These results suggest that during the preschool years, children begin to expect to be asked for their opinion in a decision, and they accept disadvantageous decisions if they feel that they have had a voice in the decision-making process.

One for You, One for Me: Humans' Unique Turn-Taking Skills.

Long-term collaborative relationships require that any jointly produced resources be shared in mutually satisfactory ways. Prototypically, this sharing involves partners dividing up simultaneously available resources, but sometimes the collaboration makes a resource available to only one individual, and any sharing of resources must take place across repeated instances over time. Here, we show that beginning at 5 years of age, human children stabilize cooperation in such cases by taking turns across instances of obtaining a resource. In contrast, chimpanzees do not take turns in this way, and so their collaboration tends to disintegrate over time. Alternating turns in obtaining a collaboratively produced resource does not necessarily require a prosocial concern for the other, but rather requires only a strategic judgment that partners need incentives to continue collaborating. These results suggest that human beings are adapted for thinking strategically in ways that sustain long-term cooperative relationships and that are absent in their nearest primate relatives.

Procedural justice in children: Preschoolers accept unequal resource distributions if the procedure provides equal opportunities.

When it is not possible to distribute resources equitably to everyone, people look for an equitable or just procedure. In the current study, we investigated young children's sense of procedural justice. We tested 32 triads of 5-year-olds in a new resource allocation game. Triads were confronted with three unequal reward packages and then agreed on a procedure to allocate them among themselves. To allocate the rewards, they needed to use a "wheel of fortune." Half of the groups played with a fair wheel (where each child had an equal chance of obtaining each reward package), and the other half played with an unfair wheel. We analyzed children's interactions when using the wheel and conducted an interview with each child after the game was over. Children using the unfair wheel often decided to change the rules of the game, and they also rated it as an unfair procedure in the interview. In contrast, children who played with the fair wheel were mostly accepting of both the outcome and the procedure. Overall, we found that children as young as preschool age are already sensitive not only to distributive justice but to procedural justice as well.