Affective observation guides expectations about others' emotional reactions to unfamiliar action outcomes.

Observing others' emotional expressions facilitates individuals' expectations about the evaluations shared within a social group. This is useful for interpreting ambiguous cultural content, such as unfamiliar actions performed by others. This study investigated whether observed emotional reactions to instrumental actions are used to predict novel individuals' evaluations of those same actions (i.e., generalization), and whether they are more likely to be generalized for unfamiliar compared to familiar actions. Participants were presented with emotional expressions of observers reacting to individuals performing instrumental actions, before selecting the reaction they expected from a novel observer watching the same action performed by a new individual - generalization meaning that the novel observer was expected to elicit the same emotional expression as the initial observer. Experiment 1 found that negative reactions are generalized to predict negative evaluations of unfamiliar but not familiar actions, whereas Experiments 2 and 3 demonstrated differences in generalization and influence on expectations of positive and negative displays depending on whether familiar and unfamiliar actions were present. This study sheds light on the affective components of cultural learning, showing that the observation of others' emotional displays enables us to interpret unfamiliar social situations in the absence of direct communication.