In a new study, researchers Charles Perreault and Jonathan Paige from Arizona State University have provided compelling evidence that cumulative culture—a defining element of human evolution—emerged around 600,000 years ago. This discovery offers insights into the evolution of human technology and social behavior, suggesting that the intricate web of knowledge and cultural advancements that define our species has roots far deeper in history than previously understood.
Cumulative culture refers to the accumulation of modifications, innovations, and improvements over generations through social learning. This process allows human populations to build upon the solutions of prior generations, creating technologies and social structures that are far too complex for any single individual to invent within their lifetime.
This ability to build upon previous knowledge has enabled humans to adapt to a diverse array of ecological habitats. It’s essentially what made our civilization what it is today.
“Our species, Homo sapiens,” said Perreault, “has been successful at adapting to ecological conditions — from tropical forests to arctic tundra — that require different kinds of problems to be solved. Cumulative culture is key because it allows human populations to build on and recombine the solutions of prior generations and to develop new complex solutions to problems very quickly. The result is, 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 research scientist with the Institute of Human Origins and associate professor with the School of Human Evolution and Social Change.
A stone tool complex
To explore the origins of cumulative culture, Perreault and Paige analyzed the complexity of stone tools manufactured over the last 3.3 million years. Their research focused on understanding when stone tools transitioned from simple to complex.
This would signify the onset of cumulative cultural practices. They used a measure called the number of procedural units (PUs), counting how many PUs are required to create these tools as a measure of complexity. Think of a PU as another additional step in the manufacturing process — the more PUs, the more complex the product.
The study’s findings are striking. From around 3.3 to 1.8 million years ago, the complexity of stone tools remained relatively low, consistent with technologies that could be produced without cumulative culture. However, between 1.8 million and 600,000 years ago, the complexity of these tools began to slightly exceed this baseline, indicating the beginnings of more sophisticated manufacturing techniques.
The most significant shift occurred around 600,000 years ago, when the complexity of stone tools rapidly increased, suggesting that hominin populations had started to rely heavily on cumulative culture.
“By 600,000 years ago or so, hominin populations started relying on unusually complex technologies, and we only see rapid increases in complexity after that time as well. Both of those findings match what we expect to see among hominins who rely on cumulative culture,” said Paige, a postdoctoral researcher at the University of Missouri and ASU PhD graduate.
The birth of human civilization?
This finding fits with what we already knew about our ancestors and human evolution.
This increase in tool complexity coincides with several other important developments in human evolution. During the Middle Pleistocene epoch, which began around 780,000 years ago and ended about 125,000 years ago, Homo heidelbergensis emerged — a common ancestor of both Neanderthals and modern humans. During this period, there is also evidence of the controlled use of fire, the construction of wooden structures, and the development of more complex social behaviors.
The controlled use of fire, for instance, would have required a high level of coordination and knowledge transfer, further supporting the idea that cumulative culture was becoming a crucial aspect of hominin life. Similarly, the construction of wooden structures using hafted tools—stone blades affixed to wooden or bone handles—demonstrates a level of technological sophistication that would have been impossible at scale without cumulative cultural practices.
The researchers’ analysis also involved comparing stone tool technologies with those of nonhuman primates, such as chimpanzees, and with stone tool manufacturing experiments involving inexperienced human flintknappers. These comparisons helped establish a baseline for the complexity achievable without cumulative culture. The fact that stone tools significantly exceeded this baseline around 600,000 years ago indicates that hominins were engaging in complex social learning processes.
Understanding our species’ evolution on Earth
The research falls into the broader field of life natural research, which is a broad scientific inquiry into the natural history of life on Earth, particularly focusing on evolutionary processes that have shaped the development of various species, including humans. The study of cumulative culture fits seamlessly into this field, as it showcases how social learning and technological advancements have driven human evolution.
Life natural research is an interdisciplinary field, drawing on anthropology, archaeology, biology, and ecology to piece together the complex puzzle of our past. By examining fossil records, ancient artifacts, and modern primate behavior, researchers can trace the evolutionary pathways that led to the emergence of Homo sapiens.
In the context of cumulative culture, life natural research provides the framework for understanding how early hominins adapted to their environments and developed the sophisticated tools and social structures that characterize modern human societies. As such, this new research not only sheds light on the technological milestones of our ancestors but also reveals the intricate social dynamics that facilitated the transmission of knowledge across generations.
The study by Perreault and Paige is a prime example of life natural research in action. By analyzing stone tools and comparing them with nonhuman primate technologies, they have uncovered critical insights into the evolutionary significance of cumulative culture. Their findings highlight the importance of social learning in shaping human history and underscore the value of interdisciplinary research in unraveling the mysteries of our past.
This ability to accumulate and build upon knowledge across generations has enabled humans to adapt to a wide range of environments and challenges, setting us apart from other primates and paving the way for the complex societies we see today.
Journal Reference: Jonathan Paige, Charles Perreault. 3.3 million years of stone tool complexity suggests that cumulative culture began during the Middle Pleistocene. Proceedings of the National Academy of Sciences, 2024; 121 (26) DOI: 10.1073/pnas.2319175121
