Cockroaches have a kind of "collective memory" that emerges from social networks

Researchers at the Free University of Brussels compared solitary and group American cockroaches in a shelter-choice experiment with different light levels.

Groups that stayed more cohesive were more likely to keep their earlier shelter choice even after the lighting changed.

The result suggests a form of collective memory can emerge from social interaction alone, without any individual remembering the past.

If confirmed, the finding could reshape how scientists understand decision-making and memory in animal groups.