The central theme of Survival of the Friendliest is the evolutionary advantage of friendliness and cooperation. The authors argue that these traits have played a critical role in the success of humans as a species. Unlike the prevalent view that survival of the fittest means being the strongest or most aggressive, Brian Hare and Vanessa Woods present evidence that being friendly and cooperative has been most beneficial for our evolutionary trajectory. They explain that our ability to form social bonds, work together, and create supportive communities has allowed humans to thrive in diverse environments.

One of the authors’ key points is that friendliness and cooperation facilitated the development of complex social structures: Early humans who were able to form alliances and share resources were more likely to survive and reproduce. For instance, the ability to communicate effectively and empathize with others enabled the formation of larger social groups, which could defend against predators and hunt more efficiently. This social cohesion is illustrated through examples of hunter-gatherer societies, where mutual aid and collective action were essential for survival.

The authors underpin this theme with studies of animal behavior, particularly in species closely related to humans, such as bonobos.