Common thought patterns reflect generosity, fairness, and social context.

Humans generate thousands of thoughts each day, many of which concern other people. Yet it remains unclear whether these ongoing thoughts vary systematically across social contexts that demand meaningful social behavior, and whether they reflect individual differences in social preferences such as generosity and fairness. To address this question, we combined multidimensional experience sampling (MDES) with an altruism task administered online or in person (total N = 320). Participants made monetary sharing decisions across social contexts that varied in partner cues (distressed, neutral, unidentifiable), while intermittently reporting their ongoing thoughts using MDES. Dimensionality reduction of MDES responses using principal component analysis revealed a small set of common, interpretable, and robust thought patterns characterizing moment-to-moment cognition during social choice. Critically, the expression of these thought patterns tracked variation in social context, generosity, and model-based parameters indexing fairness preferences. Moreover, these patterns generalized to a separate non-social task that did not require social behavior, indicating that they reflect common patterns of cognition rather than task-specific artifacts. Together, these findings provide initial evidence that ongoing thought states offer reliable insights into social preferences, introducing a novel framework for studying the link between ongoing cognition and social behavior in the laboratory and everyday life.