“We were each put on earth to torment the other,” says cognitive scientist Steven Pinker of Elizabeth Bates, a psychologist who challenged the prevailing theory about how humans acquire language. Bates believed that language emerges from interactions between our brains and our environments, and that we do not have an innate language capacity. To many, that sounds like an innocuous statement. But in making these claims, Bates challenged formidable linguists like Pinker and Noam Chomsky, placing herself at the center of a heated debate that remains unresolved half a century later.