Theories of the economic evolution of societies and their diversity are critically examined, paying particular attention to the evolution of hunter-gatherer societies. An interdisciplinary approach drawing on anthropology and economics is adopted. Currently, three main stereotypes of the nature of hunter-gatherer societies exist. While these indicate that they were diverse, they fail to capture the full extent of their diversity. It is argued that this diversity increased with the passage of time and was shaped by the varied local eco-geographic conditions in which these societies evolved. This raises the question of whether this development had the same basis as speciation in the biological theory of natural selection. This is discussed and then particular attention is given to Adam Smith’s vision of the economic evolution of human societies. In conclusion, it is hypothesized that the evolutionary path of modern economies and societies has diverged from that of prehistoric societies—they have become less diverse. Modern societies may also have become more ultrasocial, a process which accelerated following the commencement of agriculture.