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Did humans develop better technologies without knowing why they worked?

The challenge was to get the wheel to roll faster down the track. Without understanding the physics, after several “generations,” French college students were able to make it happen. University of Exeter

Is it possible to develop a better technology without a deep understanding of how it works? Simply by building on what a past generation did?

Researchers say that may have been the case, at least for some of mankind’s ancient inventions such as the house, the kayak, and the bow and arrow.

They demonstrated their theory with an experiment with groups of French college students who improved a simple device over several “generations” without ever really understanding the forces at work.

The findings, detailed in a paper published Monday in Nature Human Behavior, challenge a different theory of human inventions that suggests they resulted from humans’ superior intelligence.


“We tend to explain the existence of complex technologies by saying humans have big brains and superior causal reasoning abilities,” said Maxime Derex, of the University of Exeter and the Catholic University of Lille, lead author of the study.

“But, as our study shows, you don’t have to understand how something works in order to improve it. Artifacts 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,” Derek said in a statement.

Here’s how the experiment worked:

The researchers used 14 “chains” of five French university students. The students in each chain were presented with a wheel rolling down a track that moved faster or slower depending on the adjustment of movable weights on the wheel’s four spokes.

Each student got five chances to try to make the wheel roll faster. All the students (except the first) received details of the last two attempts by the previous student in their chain.

The understanding of the students of how the device worked was later tested by presenting them with pairs of wheels with different weight configurations and asking them to predict which would roll faster, researchers said.


The study found that “the average wheel speed increased across generations while participants’ understanding did not.” (The laws of physics were at work, with two variables, the moment of inertia and the position of the center of mass, determining the wheel’s speed, researchers said.)

In a second experiment, the students were allowed to give the next student in their chain a written explanation of why they positioned their weights the way they did. “Most participants actually produced incorrect or incomplete theories despite the relative simplicity of the physical system,” said Derek. “This constrained subsequent experimentation and prevented participants from discovering more efficient solutions.”

The experiment demonstrated that “highly optimized technologies can emerge from the accumulation of many improvements made across generations linked by cultural transmission, without the need for an accurate causal understanding of the system,” the study said.

The study also involved researchers from Arizona State University and CNRS, the French science agency.

“Of course, intelligence is important for human adaptation,” Arizona State University Professor Rob Boyd said in a statement. “But it is not enough. Our unique ability to learn from each other makes possible the cumulative cultural evolution of superb adaptations - that are at best only partially understood - and this powerful tool has allowed our species to adapt and spread.”