Archeologists sometimes find ancient artifacts that show considerable sophistication. These might cause us to infer that the people of that time had a better understanding of the underlying science than we had previously given them credit for. This is because advances in technology often go hand in hand with advances in science. Technological advances upon up new frontiers for scientific investigation while new scientific theories lead to new technologies. But that link may not always exist.
This article discusses an experiment where successive generations of students were able to steadily improve a product without gaining a corresponding understanding of why the product worked better.
Researchers used “chains” of volunteers to tackle an engineering problem, with each volunteer able to learn from the last. Solutions improved with each “generation” — but those at the end of the chain had no more understanding of key concepts than their predecessors.
“We tend to explain the existence of complex technologies by saying humans have big brains and superior causal reasoning abilities,” said Dr Maxime Derex, of the University of Exeter and the Catholic University of Lille.
“But — as our study shows — you don’t have to understand how something works in order to improve it.
“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.”
The researchers said: “Most participants actually produced incorrect or incomplete theories despite the relative simplicity of the physical system.”
The findings prove the power of “cultural transmission, without the need for an accurate causal understanding of the system,” they said.
The journal article (paywall) is here and its abstract states:
Bows and arrows, houses and kayaks are just a few examples of the highly optimized tools that humans have produced and used to colonize new environments. Because there is much evidence that humans’ cognitive abilities are unparalleled, many believe that such technologies resulted from our superior causal reasoning abilities. However, others have stressed that the high dimensionality of human technologies makes them very difficult to understand causally. Instead, they argue that optimized technologies emerge through the retention of small improvements across generations without requiring understanding of how these technologies work. Here we show that a physical artefact becomes progressively optimized across generations of social learners in the absence of explicit causal understanding. Moreover, we find that the transmission of causal models across generations has no noticeable effect on the pace of cultural evolution. The reason is that participants do not spontaneously create multidimensional causal theories but, instead, mainly produce simplistic models related to a salient dimension. Finally, we show that the transmission of these inaccurate theories constrains learners’ exploration and has downstream effects on their understanding. These results indicate that complex technologies need not result from enhanced causal reasoning but, instead, can emerge from the accumulation of improvements made across generations.
I recently attended a talk and demonstration about Stone Age technology used in Ohio about 13,500 years ago. One of the items shown was a spear that could be thrown with the very high speeds needed to bring down large animals. The speeds needed were greater than could be obtained by simply throwing the spear. The early people had added an extra element that essentially added a slingshot mechanism to achieve the required speed and I was impressed at the idea behind the device and its elegant implementation. But it seems like they might have been able to arrive at it by piecemeal improvements without necessarily understanding the underlying physical principles.
This purely technological mode of development has the negative effect, as the authors of the journal article state, of constraining the range of exploration and limiting their later understanding. There is a rough analogy with evolution by natural selection. It proceeds by incremental improvements, not because of some comprehensive plan. I read an account about how evolutionary biologist Steven Jones once worked to design nozzles that would emit a better spray of liquid soap. By starting out with the design that worked best out of the ones they already had, they made small changes to it to find one those that worked better. From those, they again selected the best and made as series of small changes to it. And so on. They finally arrived at a much better nozzle than the one they started with without having had to use any basic scientific knowledge of how spray nozzles worked. But of course, the final product depended on the choices made at each step. A different, sub-optimal choice at any stage may have resulted in a superior product at the end but in the absence of an underlying scientific theory, that was not attained.
Evolution is also like that. There is no reason to think that the organisms we currently have, including humans, are the best possible result of the process because we were never part of some grand plan but instead are the end product of a series of piecemeal improvements. In fact, it is this particular feature of evolution that so arouses the ire of religious people for whom it is important that human beings be the result of a divine plan.