Pinpointing when our ancient ancestors evolved humanlike brains is a frustratingly difficult puzzle. Brains almost never fossilize, so researchers must scrutinize impressions in the skull left behind by the brain’s grooves, folds, and bulges. A new analysis of such imprints from five skulls suggests our genus, Homo, developed complex language and advanced toolmaking hundreds of thousands of years later than previously thought. Other researchers disagree with that interpretation, but say the study still sheds much-needed light on brain structures in our genus’ earliest days.