Ancient stone tools in China reveal an unexpectedly early start to human technology

Old beliefs about early human behavior in East Asia are being challenged by the discovery of a richly-layered archaeological site located in central China. The excavation project at Xigou, led by the Chinese Academy of Sciences and supported by Griffith University, has shown that the stone-creating groups living there were more adept at creating new tools than previously thought.

The research team discovered new techniques that date to between 160,000 years ago and 72,000 years ago. The discovery indicates that ancient humans in China showed foresight when developing their tools, adapted to their changing environments, and utilized composite tools. These included handles or shafts made from wood or bone.

For the past several decades, many researchers have thought that while hominid species that lived in Africa and Western Europe developed highly complex tools and methods of tool creation, those who lived in East Asia were more likely to follow a simple tradition in developing their tools. The new information released by Xigou demonstrates that the long-standing assumptions about tools in East Asia are not accurate.

"There has been a common assumption among researchers for many years that hominid species from Africa and Western Europe made major technological advances, and that hominid species from East Asia relied solely on simple and conservative stone tool traditions," said Dr. Shixia Yang, the leader of the expedition from the Institute of Vertebrate Paleontology and Paleoanthropology within the Chinese Academy of Sciences.

The site is located in the province of Henan in the Danjiangkou Reservoir Area, adjacent to the Qinling Mountain Range. The site also forms a geoclimatological boundary between northern and southern China and between two distinct ecological zones. The Liuguan River in the vicinity of the site has been affected by environmental changes and the movement of resources.

The time period represented by the items found at the site represents a critical period in evolution. Over the course of approximately 300,000 to 50,000 years, multiple hominin species with large brains lived throughout East Asia. These included the species labelled as Homo juluensis, from many archaeological sites, along with Homo sapiens.

Professor Michael Petraglia, one of the authors of the article, commented, "The Xigou evidence contradicts the traditional view of early human activity in China continuing to be conservative."

Petraglia indicated that the tool evidence from the Xigou site demonstrates that hominins used "advanced methods of producing small flakes and tools from stone to carry out a variety of tasks." This implies that hominins were capable of a broad range of creative problem-solving techniques.

Work on Xigou began in 2017, and the excavation took place between 2019 and 2021. It was planned to excavate an area of 243 square meters, with six sediment layers identified. The majority of artefacts were found in layers 2 through 5.

"Our research team tried multiple luminescence dating methods to determine how long it had been since sediment grains were buried. When we compared the results of their various methods, ReOSL dating was determined to produce the most precise and reliable results," Dr. Yang told The Brighter Side of News.

"Based on this technique and the resulting data, the main occupation layer of the site occurred between AD 160,000 and AD 72,000. Based on this range, we believe that Xigou represents the latter phase of the Middle Pleistocene to the early Late Pleistocene. This was a time of environmental instability and an increase in the diversity of hominins," he added.

The amount of small tools recovered, over 2,500, provides unique evidence of the capabilities that hominins possessed compared to other hominin groups at that time. Most of the small artefacts, 70 to 80 percent, measured less than 5 cm in length. The materials that made up the tools included primarily quartz and quartzite, which would have been accessible from nearby riverbeds.

Toolmakers produced a large quantity of flakes and fragments when creating tools, whereas they produced cores and completed tools in smaller quantities. One method of creating tools that most toolmakers employed was freehand hard-hammer percussion. In this method, stones are struck to remove sharp flakes from them.

What distinguishes these methods of removing flakes is that many of these removals were based on planned strategies. One of the most commonly used techniques to produce cores from a large flake is called the core-on-flake reduction method. This method was used consistently throughout all layers of Xigou.

This indicates that the technique was a deliberate choice by the toolmaker, rather than a solution to working with limited materials. Statistical analyses have verified that larger flakes were purposely selected by toolmakers to produce the core-on-flake technique.

The purpose of using larger flakes was to create a large number of small, sharp cutting edges repeatedly. Planned reduction techniques were used, along with a degree of flexibility in their strategies over time.

Another planned method that developed within Xigou was discoid reduction. Discoid cores were formed to produce flakes that would be removed surrounding a central surface. This enabled toolmakers to retain balance and control during the production process.

While the number of discoid cores was small, they had been used extensively. They showed considerably more removal scars than would have been evident in simpler cores. Toolmakers also employed bipolar percussion. In this technique, they placed a rock on an anvil and struck it with a hammer to produce a flake.

This technique provided toolmakers with additional flexibility in their toolmaking. Combining these methods suggests that they used a system that was efficient and adaptable.

The flakes recovered can be explained as having been removed through these methods. This confirms that the technology was intentionally developed by the toolmakers.

The most significant evidence obtained from the site of Xigou in East Asia is that basket-hilt tools were produced here. The use of a connecting handle allows greater precision and greater power over the tool.

This was the earliest example of a hafted tool found in East Asia. "These tools were constructed from stone and a handle, and it was evident that these had been designed utilizing advanced planning abilities and skilled crafts, and that constructors were familiar with techniques that enabled maximising the effectiveness of the tools they made," said the primary investigator, Dr. Jian-Ping Yue of the Institute of Vertebrate Paleontology and Paleoanthropology.

At the Xigou site, most tools were reconstructed chips used to create scrapers, borers, pointed implements, and many other tools. These tools had variations of bases, or tangs, or backs. These features would have facilitated construction by providing a point of attachment to a handle.

Microwear studies of the tools illustrate how they were likely employed. Two specimens of tanged borer tools revealed a pattern of wear suggesting use for boring through tough plant materials. This was likely reed, but with evidence of hafting.

There were also tools with signs of sawing, engraving, and whittling with respect to this hafting ability. Yue said, "The presence of these tools at the Xigou site shows that the hominins in Xigou possessed the ability to be behaviourally flexible and clever."

The findings of Xigou fit into a larger body of evidence suggesting that technological innovations in China occurred earlier than previously thought. Dr. Yang noted, "New evidence from Xigou and other localities with early Chinese technology indicates that China was home to a more developed and varied technological domain than previously thought."

The study suggests that technological advancement may have assisted hominins in adapting to changes in the environment. It also supports the notion that different hominin populations were present in the area. As described by Petraglia, "Technological systems that can be attributed to these stone tools likely played an important role in how these hominins adapted to the continually changing environments present throughout the last 90,000 years of Eastern Asia."

The findings of this study were published in Nature Communications under the title, "Technological Innovations and Hafted Technology in Central China -160,000~72,000 years ago." The study supports the revised view of human evolution in East Asia. It suggests that humans in East Asia could be described as being cognitively and technologically comparable to other early hominins throughout the world.

The archaeological findings at Xigou fundamentally change how human adaptability and innovation are viewed. These findings suggest that advanced planning, standardizing tool forms, and making composite tools developed as much independently in East Asia as they did in Africa and Europe.

The findings encourage researchers to expand their search for early innovations across the Asian continent. For humanity, they provide further evidence that the human evolutionary story is a shared account of choosing to be creative and to problem-solve when faced with changing environments.

Research findings are available online in the journal Nature Communications.

Like these kind of feel good stories? Get The Brighter Side of News' newsletter.