Why independent cultures think alike when it comes to categories

When it comes to categorization, such as interpreting and curating art, the dominant hypothesis is that people are born with categories already in their brains. But a new study from the Network Dynamics Group (NDG) at the Annenberg School for Communication has discovered a novel explanation. In an experiment in which people were asked to categorize unfamiliar shapes, individuals and small groups created many different unique categorization systems while large groups created systems that were nearly identical to one another.

Three abstract symbols in a row, part of visual a communications experiment.
Some of the unfamiliar shapes participants were shown during the experiment. (Image: Annenberg School for Communication)

“If people are all born seeing the world the same way, we would not observe so many differences in how individuals organize things,” says senior author Damon Centola, professor of communication, sociology, and engineering. “But this raises a big scientific puzzle. If people are so different, why do anthropologists find the same categories, for instance for shapes, colors, and emotions, arising independently in many different cultures? Where do these categories come from and why is there so much similarity across independent populations?”

The explanation is connected to previous work conducted by NDG on tipping points and how people interact within networks. As options are suggested within a network, certain ones begin to be reinforced as they are repeated through individuals’ interactions with one another, and eventually a particular idea has enough traction to take over and become dominant. This only applies to large enough networks, but according to Centola, even just 50 people is enough to see this phenomenon occur.

“Many of the worst social problems reappear in every culture, which leads some to believe these problems are intrinsic to the human condition,” says Centola. “Our research shows that these problems are intrinsic to the social experiences humans have, not necessarily to humans themselves. If we can alter that social experience, we can change the way people organize things, and address some of the world’s greatest problems.”

This story is from the Annenberg School for Communication.