Origins of Cumulative Culture in Human Evolution – Researchers Identify Contributions to Today’s Culture and Technology

Each of us individually is the accumulated product of thousands of generations that have come before us in unbroken succession. Our culture and technology today are also the result of thousands of years of accumulated and remixed cultural knowledge.

But when did our earliest ancestors begin to make connections and build on the knowledge of others, distinguishing us from other primates? Cumulative culture—the accumulation of technological modifications and improvements over generations—allowed humans to adapt to diverse environments and challenges. However, it is not clear when cumulative culture first developed during hominin evolution.

A study published this week in Proceedings of the National Academy of Sciences Arizona State University researcher Charles Perreault and doctoral student Jonathan Paige concluded that humans began to rapidly accumulate technological knowledge through social learning about 600,000 years ago.

“Our species, Homo sapiens,” Perreault said, “has successfully adapted to ecological conditions—from tropical forests to arctic tundra—that require solving different kinds of problems. Cumulative culture is key because it allows human populations to build on and recombine the solutions of previous generations and very quickly develop new complex solutions to problems.

“As a result, our cultures, from technological problems and solutions to how we organize our institutions, are too complex for individuals to invent on their own.” Perreault is a researcher at the Institute of Human Origins and an associate professor at the School of Human Evolution and Social Change.

To determine 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 explore the origins of the Cumulative Culture.

As a basis for the complexity of stone tool technologies attainable without cumulative culture, the researchers analyzed the technologies used by nonhuman primates—such as chimpanzees—and stone tool-making experiments involving inexperienced human flints and random flaking.

Researchers have broken down the complexity of stone tool technologies by the number of steps (PUs or procedural units) that each tool-making sequence involved. The results suggest that from about 3.3 to 1.8 million years ago—when Australopithecus and the earliest Homo species were around—stone tool production sequences remained within the baseline range (1 to 6 PU).

Around 1.8 million to 600,000 years ago, production sequences began to overlap and slightly exceed the complexity baseline (4 to 7 PU). But about 600,000 years ago, the complexity of production sequences increased rapidly (5 to 18 PUs).

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

Foraging with tools may have been the impetus for the earliest beginning of the evolution of cumulative culture. Early hominins, 3.4 to 2 million years ago, likely relied on foraging strategies that required tools such as access to flesh, bone marrow, and organs, leading to changes in brain size, lifespan, and biology that paved the way for cumulative culture.

While other forms of social learning may have influenced tool production, it is not until the Middle Pleistocene that there is evidence of a rapid increase in technological complexity and the development of other kinds of new technology.

The Middle Pleistocene also shows consistent evidence for the controlled use of fire, hearths, and domestic spaces, probably essential components of the development of a cumulative culture. Other types of complex technology also developed in the Middle Pleistocene, including wooden structures constructed from logs carved with hooked tools, which are stone blades attached to wooden or bone handles.

All of this suggests that a cumulative culture arose near the beginning of the Middle Pleistocene epoch, perhaps predating the divergence of Neanderthals and modern humans.