The normal operation of healthcare systems necessitates a variety of pro-social behaviours. There is usually a chronic shortage of organs to transplant, blood from donors of specific types, and other biological material donations that make a huge difference in people's lives, such as breast milk donations, which are critical for feeding premature children. This chronic shortage is distinguished by the fact that demand is consistently far greater than supply. Hence a question this chapter will try to address is how can we incentivise desirable pro-social behaviours? How do individuals react to health inequality? How should social decision-making be reconsidered when we consider the fact that individuals face cognitive biases? Social preferences include certain types of pro-social behaviours such as altruism and reciprocity, as well as a genuine preferences against inequity. The chapter discusses explanations for social preference behaviours and the motivation and incentives of pro-social behaviours and the role of altruism in health. Finally, we examine inequality aversion, namely how sensitive people are to inequality.