Ancient Humans Might Not Have Been as Clever as We Thought

wheel experiment
The participants could modify the position of 4 weights attached to the wheel's spokes, in an attempt to increase its speed along the sloping rail. Maxime Derex

When we look back over the course of human history, it is easy to marvel at the ingenuity behind simple but incredibly effective technologies—like houses, boats or bows and arrows—which had such a profound impact on the lives of our ancestors.

Many believe that such technologies are evidence of humans' superior reasoning abilities. However, an experimental study published in the journal Nature Human Behavior suggests that ancient peoples did not necessarily have a sophisticated understanding of how these tools worked.

In the paper, an international team of authors instead argues that enhancements in the designs of certain technologies over time could have been the result of an accumulation of many, mostly small and poorly understood modifications where successive generations did not have to have a greater understanding of the technology compared to previous ones in order to make it better. This is known as the "cultural niche hypothesis," according to the researchers.

"It is often believed that humans succeeded in producing complex tools and adapting to different environments thanks to their impressive brain," Maxime Derex, from the University of Exeter and the Catholic University of Lille, told Newsweek. "Yet the effectiveness of traditional technologies such as bows or kayaks depends on numerous parameters that remain difficult to understand and model, even for modern physicists."

"Some anthropologists have consequently suggested that these technologies result not from our reasoning abilities, but from our propensity to copy other members of our group," she said.

To test the hypothesis that technological improvements can emerge over time without greater individual understanding, the researchers asked French college students—who each represented a different "cultural generation" for the purposes of the experiment—to try and optimize a simple physical system.

The system consisted of a wheel with four spokes that traveled down a 1-meter-long inclined track. Each spoke had a weight which could be moved onto other spokes in different configurations to make the wheel move faster or slower. The researchers tasked the students with trying to make the wheel travel as fast as possible down the track using different set-ups.

The participants were organized into 14 chains of five—with each student given five attempts at the task. The volunteers were able to "learn" from the previous individual to simulate knowledge being passed down through generations, however, at this stage, no explanations were given for why a certain configuration would work better than another.

"All participants—except those in the first generation—were provided with the last two configurations and associated scores of the previous participant in their chain to simulate overlapping generations," the authors wrote in the study. "Participants were informed that their last two trials would be transmitted to the next participant in the chain, and that their reward depended both on their own performance and on the performance of the next participant in the chain."

The researchers found that, on average, each "generation" was able to make the wheel go faster despite that the fact that those individuals at the end of the chain had no more understanding of the physics behind the enhanced solution than their predecessors. (The scientists tested participants' understanding by asking them to predict which of two wheels with different weight configurations would move down the track faster.)

"In other words, there was no link between the wheel's performance and the participants' level of understanding," Derex said.

In a subsequent portion of the experiment, the scientists gave another 14 chains of students the same task, but this time, each individual was asked to write down an explanation of their configuration to pass to the next individual.

Much like in the first portion of the experiment, each generation was able to increase the speed that the wheel traveled at a similar rate. But perhaps surprisingly, understanding of the physical system barely changed across the generations, according to the authors, despite the fact that the students could explain the theory to the next participant.

"Most participants actually produced incorrect or incomplete theories despite the relative simplicity of the physical system," the authors said.

In light of their results, the researchers came to the conclusion that knowledge can be transmitted through the generations without "an accurate causal understanding of the system."

"Artefacts from hundreds or thousands of years ago do not necessarily show that their makers had a plan or a theory about how something would work," Derex said.

"This experiment illustrates the importance of cultural processes in the emergence of complex tools, as our ability to copy other individuals enables the emergence of technologies that no single individual could have invented alone," she said. "It also encourages us to be more prudent in the interpretation of archaeological remains in terms of cognitive capacities, as these abilities are not the only driver of technological evolution."