LLMs Grow Brain-Like Modularity Without Being Built For It
Circuit analysis across 46 tasks shows LLMs spontaneously organize into specialized networks for language, formal reasoning, social cognition, and physics, mirroring the human brain's functional modularity. Because these models were optimized by a totally different process, the convergence hints modularity is a fundamental property of intelligence, not a biological accident. That raises concrete questions about interpretability and how we should architect future systems.