The study of human evolution is taking a fascinating turn thanks to a recent discovery about the behaviors of modern chimpanzees. According to new research from Bossou, Guinea, these primates select their stone tools in a similar way to Oldowan hominids, which lived 2.5 million years ago. These observations offer new insights into the origins of tool use and the parallels between the behaviors of modern primates and those of our ancestors.
A little historical and scientific context
Tool use has long been associated with human evolution. The first stone tools, known as tools everywheredate back around 3.3 million years, well before the appearance of the genus Homo. Fossils bearing traces of butchery tools also date back to this time. However, the tools Oldowayenswhich appeared around 2.5 million years ago, mark a key stage in the technological history of hominids. These rudimentary tools already reflected an understanding of specific material properties, such as hardness and fracture resistance.
In this context, primate archeology plays a crucial role. It expands our understanding of non-human primate behaviors in relation to tools, blurring the boundary between human and animal. Understanding how modern primates use and select tools can notably shed light on the cognitive processes involved in our ancestors, revealing unexpected similarities in how these species interact with their environments.
The Bossou chimpanzee study
In Bossou, chimpanzees are known for their sophisticated use stone tools for cracking nuts. The researchers, led by David Royce Braun, introduced new stones, unknown to chimpanzees, to examine their selection behaviors. Each stone was assessed for its mechanical properties, such as hardness, strength and elasticity, to determine whether these characteristics influenced the chimpanzees' choices.
The results show that these primates do not choose their tools at random; they prefer harder stones for hammers and softer stones for anvils, thus optimizing their efficiency. For example, harder stones require fewer blows to crack a nut, while softer stones reduce the risk of the anvil fracturing. This behavior reveals a intuitive understanding of material properties, even when they are not visible to the naked eye.
The study also showed that young chimpanzees learn by observing adults, often reusing tools already selected. This knowledge transfer highlights the importance of social learning in primate culture.
Parallels with ancient hominids
Oldowan tools, discovered in archaeological sites in Africa, show that our ancestors were just as selective in their choice of materials. They favored specific stones for their ability to fracture cleanly or resist wear. Although Oldowan hominids may not have had a conscious understanding of the mechanical properties of stones, their choices reflect a process of collective learning and experimentation, similar to that observed in modern chimpanzees.
This discovery, published in the Journal of Human Evolution, raises an intriguing question: Were the cognitive mechanisms involved in tool selection fundamentally different between ancient hominids and non-human primates? Chimpanzees show that relatively simple processes, such as individual and social learning, are enough to develop effective technology. Hominids may have adopted similar approaches before more sophisticated forms of cultural transmission developed.
What scientific implications?
The implications of this study extend beyond understanding chimpanzees; they redefine our vision of the beginnings of human technology and highlight the common cognitive bases shared by primates and hominids. It also highlights the importance of social learning in tool development, a process that may lie at the origin of human culture.
These results could also help archaeologists better interpret the material record of early tools. If modern chimpanzees can select and use tools in such sophisticated ways, this complicates the task of distinguishing artifacts produced by hominids from those generated by nonhuman primates in ancient archaeological contexts.
The study also opens up numerous avenues of research. For example, it would be interesting to examine whether other populations of chimpanzees or other primates show similar behaviors. Researchers could also study how social factors, such as tool sharing or interactions between groups, influence material selection.
Additionally, the research raises questions about how ancient hominids passed on their knowledge of tools. Did they learn by observing other individuals, like chimpanzees, or did they develop more sophisticated methods of communication and teaching?
Future studies could explore these mechanisms by integrating analyzes of archaeological sites, controlled experiments with primates, and cognitive modeling.
