Humans inhabit the widest range of ecological and social niches of any mammal. Yet each ecological and social environment presents a set of challenges that we must solve in order to successfully inhabit it. We are able to do so by building institutions that can flexibly respond to changing circumstances. Institutions that solve adaptive challenges necessary for human sociality, such as how to resolve conflicts, find mates, and extract and distribute resources, are termed locally adaptive institutions. The design of locally adaptive institutions promotes coordination and cooperation among unrelated individuals, reflecting the constraints of the particular ecological and social challenges to which they are responsive. Institutions generally are enabled by a suite of social and psychological mechanisms, including norm compliance, self-interested design, selective imitation, and cultural group selection among others. The development of locally adaptive institutions are likely to be especially shaped by self-interested design in which agents are sensitive to the payoffs from various norms and choose to enforce and follow those which they anticipate to be most beneficial to themselves. Exogenous shocks, including the advent of material and cultural technologies, population pressures, or even group conflict can contribute to the modification of existing social institutions and the development of new social structures. Using several case examples from traditional east African pastoralist societies, I illustrate how ecological and social pressures shape the development of social norms that underlie locally adaptive social institutions and facilitate continued cooperation in the face of change at scales ranging from local to global.

人类居住在任何哺乳动物中最广泛的生态和社会生态位。然而，每个生态和社会环境都提出了一系列挑战，我们必须解决这些挑战才能成功地栖息在其中。我们能够通过建立能够灵活应对不断变化的环境的机构来做到这一点。解决人类社会所必需的适应性挑战的制度，例如如何解决冲突、寻找配偶以及提取和分配资源，被称为当地适应性制度. 当地适应性机构的设计促进了无关个人之间的协调与合作，反映了他们应对的特定生态和社会挑战的限制。制度通常由一套社会和心理机制支持，包括规范遵守、自利设计、选择性模仿和文化群体选择等。本地适应性制度的发展很可能特别受自利设计的影响，在这种设计中，代理人对各种规范的回报很敏感，并选择执行和遵循他们预期对自己最有利的那些。外来冲击，包括物质和文化技术的出现、人口压力、甚至群体冲突都可能有助于改变现有社会制度和发展新的社会结构。我使用来自传统东非牧民社会的几个案例来说明生态和社会压力如何影响作为当地适应性社会制度基础的社会规范的发展，并在面对从地方到全球范围的变化时促进持续合作。