The formation of societies also requires an ability to tolerate others and to live with unrelated neighbours. Coupled with this is our ability to form and accept hierarchies. If everyone felt a need to lead or be in charge, stable social structures could not evolve or persist. We are also able to distribute specialist tasks among members of a group of individuals in ways that are rare in the animal kingdom. It is not necessary for everyone to hunt large game, build houses, forage or cook. Each of us does not need to be capable of fulfilling all roles within society or an organization, but we can deploy our expertise while allowing others to do the same. Some redundancy is useful, as having two or three people who can hunt or cook in a group can provide backup if one is ill or injured. A third phenotypic trait is our ability to behave and make decisions now that may not be rewarded until some point in the future. We invest in stocks and shares to reap the possible returns at a later date.
Although these characteristics are key to our success, they don’t always result in the same social structures, organizations or civilizations emerging. Humans are very flexible, and even in relatively small groups working together, different social structures emerge. The collaborative research group I have worked with on sheep and deer tended to be hierarchical, individuals tended to have quite strongly held opinions on the type of science that should be done, and there was little flexibility. In contrast, the group I have worked with on the guppies is much less hierarchical, more flexible and more open to new ideas. The wolf scene is much more political, in part because the presence of wolves in Montana, Idaho and Wyoming is contentious, and although the team are open to new ideas, there is always concern about political fallout. The sheep, guppy and wolf collaborative research groups have all been successful, and there is clearly no right or wrong way for scientific collaborations to function. Who knows, perhaps the different cultures arose because we simply end up resembling our study organisms? Sheep and deer form social hierarchies and can be pretty stubborn, guppies are less socially organized and highly adaptable, while wolves are highly social balancing within and between pack dynamics. I am sure I have changed as I have switched between study systems.
It is not just research collaborations that can culturally differ, so too do nation states. Different countries have different social, political and economic structures, with some being more open and others more dictatorial. Some societies are driven by religious doctrines, others are sectarian. There are many ways we organize ourselves, and many ways for societies and organizations to succeed. All this flexibility stems from our intelligence, the fact we are social, and our ability to think abstract thoughts.
Identifying at which points during human evolution these characteristics emerged is not entirely straightforward. Decision-making abilities, for example, do not fossilize. Even anatomical evidence can be a challenge to interpret: the evolution of an anatomical structure that allows vocalization of particular sounds does not provide evidence of language. Many birds, for example, are excellent mimics, with some species being able to repeat words and sentences with astonishing accuracy, but this is not an ability to communicate articulately in the way that we do. Palaeontologists have discovered from fossils that species that may well have been our ancestors had the anatomical ability to make a very wide range of noises at least 25 million years ago, yet they hypothesize that complex language evolved less than 2 million years ago. Related to this is the degree of language complexity needed to form a complex society. Are past, present and future tenses required, and what about conditional arguments? Apparently not, as some modern languages do not have all these tenses. I wonder if this book will be translated into one of those? Do individuals need a vocabulary of ten, a hundred, a thousand, or ten thousand words? It is presumably fewer than the average number of words we use today. The average English speaker knows about 40,000 words but has an active vocabulary of about half that number. Did inhabitants of the first cities 9,500 years ago know so many words?
Despite the challenges of working out when the key attributes required to live in complex societies first appeared in our ancestors, palaeontologists and anthropologists have made progress in identifying some key events, and some consensus has emerged. The first appearance of cave art, types of tools, jewellery and trinkets, evidence of deliberate burial, and use of fire all provide clues to the abilities of our ancestors. Other evidence is harder to interpret. Homo erectus was a hugely successful ancestral species of ours that dispersed from Africa into Europe and Asia. Populations of Homo erectus established on islands such as Flores and Java in Indonesia that could only be colonized by crossing tracts of ocean. Some scientists have argued this is evidence of seafaring abilities that would have required some form of language, while others contend that arrivals would more likely have been accidental, with individuals carried across on rafts of vegetation washed out to sea following ancient tsunamis. This latter perspective has Homo erectus as a species with an anatomy like ours but that lacked humanity. Without additional evidence, the debate cannot be confidently resolved, although I have an opinion that I will share later. What is agreed is that many skeletons from Flores were of a hobbit-sized race. Many species of large mammal including elephants, deer, rhinos and hippos evolve to smaller sizes on islands, and Homo erectus may have shown this pattern too, yet palaeontologists do not agree on this either, with some arguing the fossils are from individuals that may have been inbred, and that the diminutive size was due to developmental abnormalities rather than evolution. Evolutionary biologists also do not agree on what drives large species to evolve to smaller sizes on oceanic islands, but they hypothesize that a lack of predators, competitors or more benign island climates may play a role.
Telling the narrative of how humans evolved attributes enabling them to develop complex societies, and then how they then deployed them to do so, is difficult because the field of human evolution is fast-moving. Each new fossil find can lead to re-evaluation of significant aspects of the sequence of events. Two authors, David Graeber and David Wengrow, have recently produced a remarkably well-researched book, The Dawn of Everything: A New History of Humanity, which provides a major revision of previously accepted wisdom on humanity’s roots. It has not been met with universal approval in the popular press or in the fields of archaeology and anthropology, but attempts to revise history rarely are. I found the arguments compelling. The debate the book’s publication has sparked arises because there are relatively few data from our ancient past and interpreting them is like trying to describe the picture on a jigsaw puzzle with only a small fraction of pieces to hand.
The story I tell below is my interpretation of the current evidence. It is my conclusion that Homo erectus, one of our recent ancestors, was intelligent but not as intelligent as humans, but that Neanderthals and the first Homo sapiens had cognitive abilities very similar to ours. These latter species were not the dumb cavemen and -women so often portrayed in some popular books and documentaries. The rise of civilization took time because for it to happen, certain technologies needed to be invented, but such technologies only became necessary and useful at certain points in our history. There was no requirement to develop them beforehand. These points in our history were determined by food availability, climate and competition between different groups of hunter-gatherers. The story of the rise of complex societies is a narrative of how technology our ancestors developed forced behavioural changes upon us. We are a product of our technologies, and likely will be into the future too.