According to the passage, the concept of social cooperation involves which of the following?

Human beings are not completely free to socially construct their own behaviour. They have a shared biological nature. This nature is remarkably uniform throughout the world, given the fact that most contemporary humans outside of Africa descended from a single relatively small group of individuals some fifty thousand years ago. This shared nature does not determine political behaviour, but it frames and limits the nature of institutions that are possible. It also means that human politics is subject to certain recurring patterns of behaviour across time and across cultures. This shared nature can be described in certain propositions, like that human beings never existed in a pre-social state. The idea that human beings at one time existed as isolated individuals, who interacted either through anarchic violence (Hobbes) or in pacific ignorance of one another (Rousseau), is not correct. Human beings, as well as their primate ancestors, always lived in kin-based social groups of varying sizes. Indeed, they lived in these social units for a sufficiently long period of time that the cognitive and emotional faculties needed to promote social cooperation evolved and became hardwired in their genetic endowments. This means that a rational-choice model of collective action, in which individuals calculate that they will be better off by cooperating with one another, vastly understates the degree of social cooperation that exists in human societies and misunderstands the motives that underlie it. The next idea is that of natural human sociability. This is built around two principles, kin selection and reciprocal altruism. The principle of kin selection, or inclusive fitness, states that human beings will act altruistically toward genetic relatives (or individuals believed to be genetic relatives) in rough proportion to their shared genes. The principle of reciprocal altruism says that human beings tend to develop relationships of mutual benefit or mutual harm as they interact with other individuals over time. Reciprocal altruism, unlike kin selection, does not depend on genetic relatedness; it does, however, depend upon repeated, direct personal interaction.