How do humans learn, through social interaction, whom to depend on in different situations? We compared the extent to which inferred trait attributes-as opposed to learned reward associations previously examined as part of feedback-based learning-could adaptively inform cross-context social decision-making. In four experiments, participants completed a novel task in which they chose to "hire" other players to solve math and verbal questions for money. These players varied in their trait-level competence across these contexts and, independently, in the monetary rewards they offered to participants across contexts. Results revealed that participants chose partners primarily based on context-specific traits, as opposed to either global trait impressions or material rewards. When making choices in novel contexts-including determining who to choose for social and emotional support-participants generalized trait knowledge from past contexts that required similar traits. Reward-based learning, by contrast, demonstrated significantly weaker contextsensitivity and generalization. These findings suggest that people form context-dependent trait impressions from interactive feedback and use this knowledge to make flexible social decisions. These results support a novel theoretical account of how interaction-based social learning can support context-specific impression formation and adaptive decision-making.

To build social ties, humans need to find others who want to interact with them. How do people learn, over time, to interact with partners who want to affiliate with them? Theories of social cognition suggest that people try to infer whether others value them, but theories of instrumental learning suggest that rewarding outcomes reinforce choices. In three studies, we provide evidence that both social acceptance outcomes and cues to a partner’s acceptance intentions reinforce social partner choices. Even when outcomes were experimentally dissociated from a partner’s intentions, outcomes influenced how people felt, which partners people chose, and how well people believed they were liked by partners. Finally, people acted kindlier both to partners who demonstrated acceptance intentions and to partners who provided acceptance outcomes. These findings support an integrative instrumental learning model of social affiliation, wherein social cognition and rewarding outcomes jointly shape affect, partner choice, and prosocial behavior.

Our memories of other people shape how we interact with them. Yet, even when we forget exactly what others said or did, we often remember impressions that capture a general gist of their behavior—whether they were forthright, friendly, or funny. Drawing on fuzzy trace theory, we propose two modes of social impression formation: impressions formed based on ordinal gist (“more competent,” “less competent”) or categorical gist (“competent,” “incompetent”). In turn, we propose that people gravitate toward the simplest representation available and that different modes of memory have distinct consequences for social decisions. Specifically, ordinal impressions lead people to make decisions based on an individual’s standing relative to others, whereas categorical impressions lead people to make decisions based on discrete classifications that interpret behavior. In four experiments, participants learned about two groups of individuals who differed in their competence (Studies 1a, 2, and 3) or generosity (Study 1b). When participants encoded impressions as ordinal rankings, they preferred to hire or help a relatively good target from a low-performing group over a relatively bad target from a high-performing group, even though both targets behaved identically and accuracy was incentivized. However, when participants could use categorical boundaries to interpret behavior, this preference was eliminated. In a final experiment, changing the category participants used to encode others’ generosity changed their impressions, even when accounting for memory for verbatim details. This work links social impressions to theories of mental representation in memory and judgment, highlighting how distinct representations support divergent patterns of social decision-making.