New research reveals origins of cumulative culture in human evolution

Our modern culture and technology are derived from millennia of cultural knowledge continually accumulated and reinterpreted.

We are each the culmination of thousands of generations that have preceded us in an unbroken lineage. Likewise, our current culture and technology evolved from millennia of accumulated and reinvented cultural knowledge.

But when did our earliest ancestors begin to make connections and build on each other’s knowledge, thereby distinguishing us from other primates? Cumulative culture – the accumulation of technological changes and improvements over generations – has allowed humans to adapt to a diversity of environments and challenges. But it’s unclear exactly when cumulative culture first developed during hominid evolution.

A study recently published in the Proceedings of the National Academy of Sciences by Charles Perreault, a researcher at Arizona State University, and Jonathan Paige, a doctoral student, concludes that humans began rapidly accumulating technological knowledge through social learning around 600,000 years ago.

« Notre species, A wise man“, Perreault said, “has managed to adapt to ecological conditions – from tropical forests to arctic tundra – that require solving different types of problems. Cumulative culture is essential because it allows human populations to build on and recombine the solutions of previous generations and develop complex new 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 invent 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.

Stone tool complexity and cumulative culture

To determine when this technological turning point may have begun, Paige and Perreault analyzed changes in the complexity of stone tool-making techniques over the 3.3 million years of the archaeological record to explore the origin of cumulative culture.

As a baseline for the complexity of stone tool technologies achievable without cumulative culture, the researchers analyzed technologies used by nonhuman primates – such as chimpanzees – and stone tool making experiments involving stone knappers. inexperienced human flints and random chipping.

Researchers have broken down the complexity of stone tool technologies according to the number of steps (PUs or procedural units) involved by each toolmaking sequence. The results suggest that around 3.3 to 1.8 million years ago – when australopiths and the first Homo species were present – ​​stone tool making sequences remained within the reference range (1 to 6 PU). Around 1.8 million to 600,000 years ago, manufacturing sequences began to overlap and slightly exceed the complexity base (4 to 7 PUs). But for around 600,000 years, the complexity of manufacturing sequences has rapidly increased (5 to 18 PUs).

“About 600,000 years ago, hominid populations began to rely on unusually complex technologies, and we only see a rapid increase in complexity after that as well. Both of these results are consistent with what we expect to see in hominids that rely on cumulative culture,” said Paige, a postdoctoral researcher at the University of Missouri and a Ph.D. from ASU.

Tool-assisted foraging may have been the first beginning of the evolution of cumulative culture. Early hominids, 3.4 to 2 million years ago, likely relied on foraging strategies that required tools, 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 making, it was not until the Middle Pleistocene that we see a rapid increase in technological complexity and the development of other types of new technologies .

The Middle Pleistocene also shows consistent evidence for controlled use of fire, hearths, and domestic spaces, likely essential elements in the development of a cumulative culture. Other types of complex technology also developed in the Middle Pleistocene, including wooden structures built with logs hewn using hafted tools, which are stone blades attached to wooden or bone handles .

All of this suggests that cumulative culture arose around the start of the Middle Pleistocene epoch, perhaps before the divergence between Neanderthals and modern humans.