Human infants appreciate that information bears value for other individuals.

Humans' ability to recognize each other as seekers of information is crucial for effectively sharing knowledge, evaluating confidence, and reasoning about the role of knowledge in behavior. Here, we investigate the foundations of this 'epistemic sense' through a series of looking-time experiments, asking whether 14-month-old human infants recognize and evaluate the information-directed goals behind others' actions. In Experiments 1-3, we assess infants' understanding of scenarios where an individual seeks information driven by uncertainty or curiosity about objects. In Experiment 4, we examine their expectations regarding the efficiency of such information seeking. Our results indicate that infants have a nuanced grasp of the principles guiding others' epistemic actions, including how uncertainty and novelty motivate information seeking, and that they also have expectations about the efficiency of such attempts in terms of maximizing information gain. This suggests that the foundational concepts for understanding the epistemic aspects of others' behavior develop early on.