Infants in laboratory settings look longer at impossible than possible events, learn better about objects that behave surprisingly, and match people's utterances to the objects that likely elicited them. The paradigms that reveal these behaviors have become cornerstones of research on preverbal cognition. But less is known about whether these canonical behaviors generalize in naturalistic environments. Here we describe a series of online protocols that replicate classic laboratory findings, detailing our methods throughout. In Experiment 1, we found that 15-month-olds (N = 24) looked longer at an online impossible support event (an object appearing to defy gravity) than a possible support event. These infants did not, however, show the same success with an online solidity event. In Experiment 2, we found that 15-montholds (N = 24) showed surprise-induced learning online-they were better able to learn a label for a novel object when the object had just behaved unexpectedly. Finally, in Experiment 3, we found that 16-month-olds (N = 20) who heard a valenced utterance ("Yum!") showed preferential looking to the object most likely to have generated that utterance. Together, these results suggest that, with some adjustments, testing infants online is a feasible and promising approach for cognitive development research.

The question of how people’s preferences are shaped by their choices has generated decades of research. In a classic example, work on cognitive dissonance has found that observers who must choose between two equally attractive options subsequently avoid the unchosen option, suggesting that not choosing the item led them to like it less. However, almost all of the research on such choice-induced preference focuses on adults, leaving open the question of how much experience is necessary for its emergence. Here, we examined the developmental roots of this phenomenon in preverbal infants ( N = 189). In a series of seven experiments using a free-choice paradigm, we found that infants experienced choice-induced preference change similar to adults’. Infants’ choice patterns reflected genuine preference change and not attraction to novelty or inherent attitudes toward the options. Hence, choice shapes preferences—even without extensive experience making decisions and without a well-developed self-concept.

No abstract

A friend telling you good news earns them a smile while witnessing a rival win an award may make you wrinkle your nose. Emotions arise not just from people's own circumstances, but also from the experiences of friends and rivals. Across three moderated, online looking time studies, we asked if human infants hold expectations about others’ vicarious emotions and if they expect those emotions to be guided by social relationships. Ten‐ and 11‐month‐old infants (N = 154) expected an observer to be happy rather than sad when the observer watched a friend successfully jump over a wall; infants looked longer at the sad response compared to the happy response. In contrast, infants did not expect the observer to be happy when the friend failed, nor when a different, rival jumper succeeded; infants’ looking times to the two emotion responses in these conditions were not reliably different. These results suggest that infants are able to integrate knowledge across social contexts to guide expectations about vicarious emotional responses. Here infants connected an understanding of agents’ goals and their outcomes with knowledge of social relationships to infer an emotion response. Biased concern for friends but not adversaries is not just a descriptive feature of human relationships, but an expectation about the social world present from early in development. Further, the successful integration of these information types welcomes the possibility that infants can jointly reason about goals, emotions, and social relationships under an intuitive theory of psychology.RESEARCH HIGHLIGHTS 11‐month‐old infants use knowledge of relationships to make inferences about others’ vicarious emotions. In Experiment 1 infants expected an observer to respond happily to a friend's success but not their failure. Experiments 2 and 3 varied the relationship between the observer and actor and found that infants’ expectation of vicarious happiness is strongest for positive relationships and absent for negative relationships. The results may reflect an intuitive psychology in which infants expect friends to adopt concern for one another's goals and to thus experience one another's successes as rewarding.