Social Decisions from Description Compared to Experience Rely on Different Cognitive and Neural Processes

Social decisions reveal the degree to which people consider societal needs relative to their own desires. Although many studies showed how social decisions are taken when the consequences of actions are given as explicit information, little is known about how social choices are made when the relevant information was learned through repeated experience. Here, we compared how these two different ways of learning about the value of alternatives (description versus experience) impact social decisions in 147 healthy young adult humans. Using diffusion decision models, we show that, although participants chose similar outcomes across the learning conditions, they sampled and processed information differently. During description decisions, information sampling depended on both chosen and foregone rewards for self and society, while during experience decisions sampling was proportional to chosen outcomes only. Our behavioral data indicate that description choices involved the active processing of more information. Additionally, neuroimaging data from 40 participants showed that the brain activity was more closely associated with the information sampling process during description relative to experience decisions. Overall, our work indicates that the cognitive and neural mechanisms of social decision making depend strongly on how the values of alternatives were learned in addition to individual social preferences.