The relative efficiency of an action is a central criterion in action control and can be used to predict others’ behavior. Yet, it is unclear when the ability to predict on and reason about the efficiency of others’ actions develops. In three main and two follow-up studies, 3- to 6-year-old children (n = 242) were confronted with vignettes in which protagonists could take a short (efficient) path or a long path. Children predicted which path the protagonist would take and why the protagonist would take a specific path. The 3-year-olds did not take efficiency into account when making decisions even when there was an explicit goal, the task was simplified and made more salient, and children were questioned after exposure to the agent’s action. Four years is a transition age for rational action prediction, and the 5-year-olds reasoned on the efficiency of actions before relying on them to predict others’ behavior. Results are discussed within a representational redescription account.
Humans are not merely passive perceivers of other people’s behavior but rather have active expectations about how others’ actions unfold over time. Importantly, this is not only true for adults (Clark, 2013; Falck-Ytter, 2012; Fogassi et al., 2005); even young children predict other people’s future behavior (e.g., Boseovski, Chiu, & Marcovitch, 2013; Clement, Bernard, & Kaufmann, 2011; Grant & Mills, 2011; Poulin-Dubois, Brooker, & Chow, 2009). Infants attend to various characteristics of others’ actions (for a review, see Gredebäck & Daum, 2015), segment the stream of others’ actions into meaningful events (Friend & Pace, 2011; Pace, Carver, & Friend, 2013), and detect the failure of others’ behavior (Brandone & Wellman, 2009). Besides this, more complex abilities and a more differentiated understanding of human behavior seem to develop, based on these earlier competences, through the preschool years (Clement et al., 2011). Children’s perception and prediction of others’ behavior is related to their social competence (Slaughter, Imuta, Peterson, & Henry, 2015), and their capacity to predict others’ actions develops profoundly over the preschool years (Monroy, Gerson, & Hunnius, 2017; Schuwerk & Paulus, 2016). Consequently, the ontogenetic origins and early development of action prediction is a topic of vivid discussion in developmental psychology.