The human brain does not develop uniformly. Areas that are devoted to basic senses mature first, whereas those that support abstract thought take decades to reach their full potential. These broad maturational trajectories have been previously established for structural properties (such as volume and thickness) of different parts of the brain1, but charting the arcs of functional organization in a similar way has been an ongoing challenge. Writing in Nature, Taylor et al.2 provide such a chart, tracking how three fundamental axes of brain organization emerge, mature and decline across the human lifespan.…