New research unravels the origins of cumulative culture in human evolution

Our modern culture and technology emerge from millennia of cultural knowledge that has been continually collected and reinterpreted.

We are all the culmination of thousands of generations that have gone before us in an unbroken line. Likewise, our current culture and technology have evolved from millennia of accumulated and reshaped cultural knowledge.

But when did our earliest ancestors begin making connections and building on the knowledge of others that set us apart from other primates? Cumulative culture – the accumulation of technological changes and improvements over generations – allowed people to adapt to a diversity of environments and challenges. But it is unclear when cumulative culture first developed during hominin evolution.

A study recently published in the Proceedings of the National Academy of Sciences (PNAS) by Arizona State University researcher Charles Perreault and PhD candidate Jonathan Paige, concludes that humans began rapidly acquiring technological knowledge through social learning about 600,000 years ago.

“Us kind, Homo sapiens‘, said Perreault, ‘has managed to adapt to ecological conditions – from tropical forests to Arctic tundra – that require solving different types of problems. Cumulative culture is critical because it allows human populations to build on and recombine the solutions of previous generations, and to develop new complex solutions to problems very quickly. The result is that our cultures, from technological problems and solutions to the way we organize our institutions, are too complex for individuals to figure out on their own.” Perreault is a research scientist at the Institute of Human Origins and an associate professor at the School of Human Evolution and Social Change.

Acheulean cleaver, Algeria. Second time period, around baseline. Credit: Curry, Michael. 2020. Acheulean Cleaver, Morocco, Koobi Fora. Stone Tool Museum. Retrieved June 10, 2024. From: https://une.pedestal3d.com/r/JMVajqyz29

Complexity of stone tools and cumulative culture

To investigate when this technological turn might have begun, Paige and Perreault analyzed changes in the complexity of stone tool-making techniques over the last 3.3 million years of the archaeological record to investigate the origins of cumulative culture.

To provide a basis for the complexity of stone tool technologies achievable without cumulative culture, the researchers analyzed technologies used by non-human primates – such as chimpanzees – and experiments in stone tool production involving inexperienced human flint beaters and random flakes .

The researchers divided the complexity of the stone tool technologies into the number of steps (PUs or procedural units) each set of tools involved. The results suggested this was about 3.3 to 1.8 million years ago – when the Australopiths existed at their earliest Homo species existed – stone tool production sequences remained within the range of baselines (1 to 6 PUs). From approximately 1.8 million to 600,000 years ago, production sequences began to overlap and slightly exceed the complexity baseline (4 to 7 PUs). But after about 600,000 years ago, the complexity of the production sequences increased rapidly (5 to 18 PUs).

Core of Levallois, late Pleistocene Algeria. Characteristic of 600 kya technologies (third period). Credit: Watt, Emma. 2020. Core of Levallois, Algeria. Museum of Stone Tools. Retrieved June 10, 2024. From: https://une.pedestal3d.com/r/JMVajqyz29

“About 600,000 years ago, hominin populations began to rely on unusually complex technologies, and even after that time we see a rapid increase in complexity. Both findings are consistent with what we expect to see in hominins that rely on cumulative culture,” said Paige, a postdoctoral researcher at the University of Missouri and a graduate of ASU.

Tool-assisted foraging may have initiated the earliest onset of cumulative culture evolution. Early hominins, 3.4 to 2 million years ago, likely relied on foraging strategies that required resources such as access to meat, marrow, and organs, leading to changes in brain size, lifespan, and biology that paved the way for cumulative culture. Although other forms of social learning may have influenced tool production, it is not until the Middle Pleistocene that there is evidence for a rapid increase in technological complexity and the development of other types of new technologies.

The Middle Pleistocene also shows consistent evidence of controlled use of fire, hearths, and domestic spaces, likely essential components of the development of cumulative culture. Other types of complex technologies also developed in the Middle Pleistocene, including wooden structures built with tree trunks carved using shafted tools, which are stone blades attached to wooden or bone handles.

All this suggests that cumulative culture emerged at the beginning of the Middle Pleistocene, possibly before the divergence between Neanderthals and modern humans.

Reference: “3.3 Million Years of Stone Tool Complexity Suggests Cumulative Culture Began During the Middle Pleistocene” by Jonathan Paige and Charles Perreault, June 17, 2024, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2319175121