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Bigger groups mean complex cultures

Two studies show that larger groups of people are better at maintaining and improving cultural knowledge.
Humanity's success depends on the ability of humans to copy, and build on, the works of their predecessors. Over time, human society has accumulated technologies, skills and knowledge beyond the scope of any single individual.

Larger groups may find it easier to improve their collective skills at tasks such as making fishing nets. Pictured are fishermen on the South coast of Sri Lanka. AGOSTINO PACCIANI/ANZENBERGER AGENCY

Now, two teams of scientists have independently shown that the strength of this cumulative culture depends on the size and interconnectedness of social groups. Through laboratory experiments, they showed that complex cultural traditions — from making fishing nets to tying knots — last longer and improve faster at the hands of larger, more sociable groups. This helps to explain why some groups, such as Tasmanian aboriginals, lost many valuable skills and technologies as their populations shrank.

“For producing fancy tools and complexity, it’s better to be social than smart,” says psychologist Joe Henrich of the University of British Columbia in Vancouver, Canada, the lead author of one of the two studies, published today in Proceedings of the Royal Society B1. “And things that make us social are going to make us seem smarter.”

“There were some theoretical models to explain these phenomena but no one had done experiments,” says evolutionary biologist Maxime Derex of the University of Montpellier, France, who led the other study, published online today in Nature2.

Derex’s team asked 366 male students to play a virtual game in which they gained points — and eventually money — by building either an arrowhead or a fishing net. The nets offered greater rewards, but were also harder to make. The students watched video demonstrations of the two tasks in groups of 2, 4, 8 or 16, before attempting the tasks individually. Their arrows and nets were tested in simulations and scored. After each trial, they could see how other group members fared, and watch a step-by-step procedure for any one of the designs.

After 15 trials, the larger groups were more likely to still be making nets as well as arrows. They had also maintained the quality of the original net design, while improving on the arrows. In smaller groups, however, the arrows never improved, and the nets became simpler over time. When most players tried to copy the tools, they ended up with less effective versions, but larger groups were more likely to contain skilled artisans who equalled or improved on the initial designs. They provided templates for their teammates to duplicate, and boosted the group’s overall performance.

Ed Yong