Over time, evolution has endowed humans with bigger, better brains, but a study of Agta hunter-gatherers in the Philippines, published in the journal Science Advances, suggests the way our societies are structured might be just as important for fuelling innovation and technological revolutions.
Humans are highly mobile and have been exchanging materials and technological know-how since at least the middle stone age. In Kenya, for instance, people travelled up to 50 kilometres to source pigments and obsidian for tool-making.
Anthropologist Andrea Migliano, from the University of Zürich, Switzerland,and colleagues wanted to find out whether the social structure of our hunter-gatherer forebears set them up for cultural progress.
For a month, they used wireless sensors to measure interactions between members of two Agta communities – a forest community and a coastal community – on the island of Luzon in the Philippines.
Like other hunter-gatherer societies, Agta society has multiple levels of organisation. Individuals belong to households. Households combine to form small camps, and several interacting camps make up a larger community.
Individuals preferentially interact with close friends or family and only transmit innovations to close kin.
Armed with this information, Migliano and her team created a computer program to simulate how a community transfers knowledge and comes up with new ideas. In the simulations, individuals shared sets of three medicinal plants with each other, gradually improving on the final drug formulations.
These step-wise improvements in two separate groups could be turbo-charged when those groups come together, creating a drug superior to either produced by the two groups.
Using interaction data from the Agta, this technological leap occurred after 177 rounds of interaction in the forest community and 516 rounds in the coastal community.
If the simulations were run with individuals sharing their innovations immediately to all other group members, innovation took longer – more than 500 rounds for the forest group, and nearly 700 rounds for the coastal group.
The finding that looser connections are better is counter-intuitive.
“Common sense would suggest that a fully connected network, or cultural open market where everyone can instantly copy new findings, would accelerate technological revolutions,” says anthropologist Lucio Vinicius from the University of Zürich, a senior author on the study.
But that’s not what the study found.
“Unrestricted flow of information eliminates cultural diversity,” says Vinicius. In the long run, he adds, that stymies progress.
“Using real hunter-gatherer social networks and then showing how they might affect cultural evolution – that’s really cool,” says evolutionary biologist Nicole Creanza from Vanderbilt University, US, who was not involved in the study.
As well as helping us understand why our ancestors were so successful, the study could have implications for the modern, digitally-connected world we live in, says Creanza.
“Knowing what everyone else is up to can be detrimental to progress,” she says. “If we can see what everyone else is doing, we get some ideas that are maybe better than our ideas.