The people around you are inside your head: Social context shapes spontaneous thought.

Humans are highly social. We spend most of our time interacting with the social world, and we spend most of our thoughts thinking about the social world. Are we social beings by default, or is our sociality a response to the social world? On the one hand, fundamental social needs may drive social behavior. According to this account, social thoughts fulfill social needs when the environment is insufficiently social. On the other hand, spontaneous thoughts may process incoming information. According to this account, social thoughts reflect the social information in the environment. To arbitrate between these possibilities, we assessed the content of spontaneous thought during mind wandering in three social contexts: solitude (Study 1), social presence (Study 2), and social interaction (Study 3). Additionally, in Study 1, we used functional neuroimaging to measure neural activity while participants considered social and nonsocial targets. Results consistently showed that spontaneous thought reflects the sociality of the world around us: Solitude decreased spontaneous social thought and decreased neural activity in the mentalizing network when thinking about a close friend. Social presence did not change spontaneous social thought. Social interaction increased spontaneous social thought. Finally, individual differences analyses (Study 4) showed that people in more social environments have more social thoughts. Together, the results show a pattern of increasing social thought in increasingly social environments. The predominance of social content in spontaneous thought can thus be explained by the predominance of social content in the world around us, rather than our innate, fundamental social needs. (PsycInfo Database Record (c) 2021 APA, all rights reserved).