Young children's adaptive partner choice in cooperation and competition contexts.

Choosing adequate partners is essential for cooperation, but how children calibrate their partner choice to specific social challenges is unknown. In two experiments, 4- to 7-year-olds (N = 189, 49% girls, mostly White, data collection: 03.2021-09.2022) were presented with partners in possession of different positive qualities. Children then recruited partners for hypothetical tasks that differed with respect to the quality necessary for success. Children and the selected partner either worked together toward a common goal or competed against each other. From age 5, children selectively chose individuals in possession of task-relevant qualities as cooperative partners while avoiding them as competitors. Younger children chose partners indiscriminately. Children thus learn to strategically adjust their partner choice depending on context-specific task demands and different social goals.

Smart or just lucky? Inferring question-asking competence from strategies' efficiency versus effectiveness.

Previous research shows that children evaluate the competence of others based on how effectively someone accomplished a goal, that is, based on the observed outcome of an action (e.g., number of attempts needed). Here, we investigate whether 5- to 10-year-old children and adults infer competence from how efficiently someone solves a task by implementing question-asking strategies of varying expected information gains (EIG). Whereas the efficiency of a strategy defined as EIG is a reliable indicator of competence, the observed effectiveness of actions may depend on unrelated external factors, such as luck. Across two experiments conducted in Germany, we varied how efficiently and how effectively different agents solved a 20-questions game (Experiments 1 and 2) and a maze-exploration game (Experiment 2). In Experiment 1 (N = 121), only adults identified a more efficient agent as more competent, and all participants attributed higher competence to agents needing fewer questions even when they employed the same inefficient strategy. In Experiment 2 (N = 220), adults and children from about 8 years onward successfully identified the agents using the more efficient strategy as more competent. Overall, our results suggest that observed effectiveness is a powerful cue for competence even when such an inference may not be warranted and that the ability to make explicit competence judgments based on the efficiency of a strategy alone emerges around 8 years of age, although, as shown in previous work, a more implicit understanding of competence may already be present during the preschool years. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Computing Joint Action Costs: Co-Actors Minimize the Aggregate Individual Costs in an Action Sequence.

Successful performance in cooperative activities relies on efficient task distribution between co-actors. Previous research found that people often forgo individual efficiency in favor of co-efficiency (i.e., joint-cost minimization) when planning a joint action. The present study investigated the cost computations underlying co-efficient decisions. We report a series of experiments that tested the hypothesis that people compute the joint costs of a cooperative action sequence by summing the individual action costs of their co-actor and themselves. We independently manipulated the parameters quantifying individual and joint action costs and tested their effects on decision making by fitting and comparing Bayesian logistic regression models. Our hypothesis was confirmed: people weighed their own and their partner's costs similarly to estimate the joint action costs as the sum of the two individual parameters. Participants minimized the aggregate cost to ensure co-efficiency. The results provide empirical support for behavioral economics and computational approaches that formalize cooperation as joint utility maximization based on a weighted sum of individual action costs.

Efficiency is prioritised over fairness when distributing joint actions.

Individuals have a drive towards maximising action efficiency, which is reflected in action choices that minimise movement costs to reach a goal. In joint actions, actors prioritise joint efficiency or coefficiency, maximising the utility of the joint action even if this comes at a cost to themselves. However, it remains an open question whether actors are willing to unilaterally sacrifice their partner's individual efficiency for the greater good, when forcing a partner to incur additional costs may be interpreted as unfair. In two experiments we explored how participants would choose to distribute a motor task that required either a fair or an unfair distribution of labour. We found that, both whether there was opportunity for reciprocity (Experiment 1) or not (Experiment 2), participants maximised the coefficiency of their joint actions, regardless of how unfair this distribution of labour proved to be regarding the individual action costs. Taken together, our results suggest participants use a rational decision-making framework that prioritises overall efficiency over both individual efficiency and a consideration of fairness.

Rationality in Joint Action: Maximizing Coefficiency in Coordination.

When people perform simple actions, they often behave efficiently, minimizing the costs of movement for the expected benefit. The present study addressed the question of whether this efficiency scales up to dyads working together to achieve a shared goal: Do people act efficiently as a group (i.e., coefficiently), or do they minimize their own or their partner's individual costs even if this increases the overall cost for the group? We devised a novel, touch-screen-based, sequential object-transfer task to measure how people choose between different paths to coordinate with a partner. Across multiple experiments, we found that participants did not simply minimize their own or their partner's movement costs but made coefficient decisions about paths, which ensured that the aggregate costs of movement for the dyad were minimized. These results suggest that people are able and motivated to make coefficient, collectively rational decisions when acting together.