Cooperation is essential for human society, and children engage in cooperation from early on. It is unclear, however, how children select their partners for cooperation. We know that children choose selectively whom to learn from (e.g. preferring reliable over unreliable models) on a rational basis. The present study investigated whether children (and adults) also choose their cooperative partners selectively and what model characteristics they regard as important for cooperative partners and for informants about novel words. Three- and four-year-old children (N = 64) and adults (N = 14) saw contrasting pairs of models differing either in physical strength or in accuracy (in labeling known objects). Participants then performed different tasks (cooperative problem solving and word learning) requiring the choice of a partner or informant. Both children and adults chose their cooperative partners selectively. Moreover they showed the same pattern of selective model choice, regarding a wide range of model characteristics as important for cooperation (preferring both the strong and the accurate model for a strength-requiring cooperation tasks), but only prior knowledge as important for word learning (preferring the knowledgeable but not the strong model for word learning tasks). Young children's selective model choice thus reveals an early rational competence: They infer characteristics from past behavior and flexibly consider what characteristics are relevant for certain tasks.

•Children witnessed a free or constrained agent perform appropriate acts or mistakes.•Children’s normative responses to moral and conventional transgressions were coded.•Children took into account the actor’s freedom of choice when evaluating her acts.•Children weighed free choice differently for different kinds of transgressions.•Normative reasoning and theory of mind judgments seem to be functionally integrated.

Much recent research has shown that the capacity for mental time travel and temporal reasoning emerges during the preschool years. Nothing is known so far, however, about young children's grasp of the normative dimension of future-directed thought and speech. The present study is the first to show that children from age 4 understand the normative outreach of such future-directed speech acts: subjects at time 1 witnessed a speaker make future-directed speech acts about/towards an actor A, either in imperative mode ("A, do X!") or as a prediction ("the actor A will do X"). When at time 2 the actor A performed an action that did not match the content of the speech act at time 1, children identified the speaker as the source of a mistake in the prediction case, and the actor as the source of the mistake in the imperative case and leveled criticism accordingly. These findings add to our knowledge about the emergence and development of temporal cognition in revealing an early sensitivity to the normative aspects of future-orientation.

Recent developmental research has shown that young children coordinate complementary action roles with others. But what do they understand about the logical structure of such roles? Do they have an agent-neutral conception of complementary action roles, grasping that such roles can be variably filled by any two agents or even by one agent over time? Accordingly, can they make use of such representations for planning both their own and others' actions? To address these questions, 3- and 4-year-olds were introduced to an activity comprising two action roles, A and B, by seeing either two agents performing A and B collaboratively or one agent performing A and B individually. Children's flexible inferences from these demonstrations were then tested by asking them later on to plan ahead for the fulfillment of one of the roles either by themselves or by someone else. The 4-year-olds competently drew inferences in all directions, from past individual and collaborative demonstrations, when planning how they or someone else would need to fulfill the roles in the future. The 3-year-olds, in contrast, showed more restricted competence; they were capable of such inferences only when planning in the immediate present. Taken together, these results suggest that children form and use agent-neutral representations of action roles by 3 years of age and flexibly use such representations for episodic memory and future deliberation in planning their own and others' actions by 4 years of age. The findings are discussed in the broader context of the development of understanding self-other equivalence and agent-neutral frames of references.

Here we investigate the extent of children's understanding of the joint commitments inherent in joint activities. Three-year-old children either made a joint commitment to assemble a puzzle with a puppet partner, or else the child and puppet each assembled their own puzzle. Afterwards, children who had made the joint commitment were more likely to stop and wait for their partner on their way to fetch something, more likely to spontaneously help their partner when needed, and more likely to take over their partner's role when necessary. There was no clear difference in children's tendency to tattle on their partner's cheating behavior or their tendency to distribute rewards equally at the end. It thus appears that by 3 years of age making a joint commitment to act together with others is beginning to engender in children a "we"-intentionality which holds across at least most of the process of the joint activity until the shared goal is achieved, and which withstands at least some of the perturbations to the joint activity children experience.

Some children's social activities are structured by joint goals. In previous research, the criterion used to determine this was relatively weak: if the partner stopped interacting, did the child attempt to re-engage her? But re-engagement attempts could easily result from the child simply realizing that she needs the partner to reach her own goal in the activity (social tool explanation). In two experiments, 21- and 27-month-old children interacted with an adult in games in which they either did or did not physically need the partner to reach a concrete goal. Moreover, when the partner stopped interacting, she did so because she was either unwilling to continue (breaking off from the joint goal) or unable to continue (presumably still maintaining the joint goal). Children of both age groups encouraged the recalcitrant partner equally often whether she was or was not physically needed for goal attainment. In addition, they did so more often when the partner was unable to continue than when she was unwilling to continue. These findings suggest that young children do not just view their collaborative partners as mindless social tools, but rather as intentional, cooperative agents with whom they must coordinate intentional states.

We investigated whether infants comprehend others’ nonverbal communicative intentions directed to a third person, in an ‘overhearing’ context. An experimenter addressed an assistant and indicated a hidden toy's location by either gazing ostensively or pointing to the location for her. In a matched control condition, the experimenter performed similar behaviors (absent-minded gazing and extended index finger) but did not communicate ostensively with the assistant. Infants could then search for the toy. Eighteen-month-old infants were skillful in using both communicative cues to find the hidden object, whereas 14-month-olds performed above chance only with the pointing cue. Neither age group performed above chance in the control condition. This study thus shows that by 14–18 months of age, infants are beginning to monitor and comprehend some aspects of third party interactions.

When adults make a joint commitment to act together, they feel an obligation to their partner. In 2 studies, the authors investigated whether young children also understand joint commitments to act together. In the first study, when an adult orchestrated with the child a joint commitment to play a game together and then broke off from their joint activity, 3-year-olds (n = 24) reacted to the break significantly more often (e.g., by trying to re-engage her or waiting for her to restart playing) than when she simply joined the child's individual activity unbidden. Two-year-olds (n = 24) did not differentiate between these 2 situations. In the second study, 3- and 4-year-old children (n = 30 at each age) were enticed away from their activity with an adult. Children acknowledged their leaving (e.g., by looking to the adult or handing her the object they had been playing with) significantly more often when they had made a joint commitment to act together than when they had not. By 3 years of age, children thus recognize both when an adult is committed and when they themselves are committed to a joint activity.