Social trust is linked to a host of positive societal outcomes, including improved economic performance, lower crime rates and more inclusive institutions. Yet, the origins of trust remain elusive, partly because social trust is difficult to document in time. Building on recent advances in social cognition, we design an algorithm to automatically generate trustworthiness evaluations for the facial action units (smile, eye brows, etc.) of European portraits in large historical databases. Our results show that trustworthiness in portraits increased over the period 1500–2000 paralleling the decline of interpersonal violence and the rise of democratic values observed in Western Europe. Further analyses suggest that this rise of trustworthiness displays is associated with increased living standards.

社会信任与许多积极的社会成果相关，包括改善经济表现、降低犯罪率和更具包容性的机构。然而，信任的起源仍然难以捉摸，部分原因是社会信任难以及时记录。基于社会认知的最新进展，我们设计了一种算法来自动生成大型历史数据库中欧洲肖像的面部动作单元（微笑、眉毛等）的可信度评估。我们的研究结果表明，肖像的可信度在 1500-2000 年期间随着人际暴力的减少和西欧观察到的民主价值观的兴起而增加。进一步的分析表明，这种可信度显示的上升与生活水平的提高有关。