Children who take music lessons develop a larger corpus callosum, the bridge between the two halves of the brain, and the change is permanent. A 2005 review in the Annals of the New York Academy of Sciences found that early music training produces structural brain changes that persist into adulthood, even if the person stops playing. The review was led by Gottfried Schlaug at Harvard Medical School, one of the leading researchers on music and the brain. He found that children who started instrumental training before age seven had a significantly larger anterior corpus callosum than non-musicians, and the size difference was still visible in adults who had not touched an instrument in years. The corpus callosum carries signals between the left and right hemispheres. A larger one means faster, richer communication between the two sides, and the effect shows up in tasks that have nothing to do with music: spatial reasoning, verbal memory, and the ability to process multiple streams of information at once. The music built the highway, and the brain uses it for everything. Schlaug also found that musicians had larger cerebellums, the region involved in timing and motor coordination, and more grey matter in the areas that process sound. The brain had physically reorganised itself around the demands of the instrument, and the reorganisation was visible on a scan. The age window matters. Children who started before seven showed the largest changes. Children who started after ten showed smaller ones. Adults who took up an instrument for the first time showed the least structural change, though they still showed some. The brain is most willing to be rebuilt by music during the years when most parents are debating whether to sign their child up for lessons. pubmed.ncbi.nlm.nih.gov/1659…

Reading a novel changes how your brain responds to other people for days after you put it down. A 2013 study at Emory University found changes in brain wiring that lasted at least five days after the book was done. Gregory Berns gave 21 students a thriller, Pompeii by Robert Harris, and assigned a chunk each evening. Every morning they came in for a scan. During the reading period, the scans showed stronger wiring in the part of the brain that handles language and places you inside a story. The brain was acting as though it were living the events of the book. The changes did not vanish overnight. They persisted into the mornings after the reading was done, even when the students were not thinking about the book. The researchers called it shadow activity, a kind of neural residue left behind by the experience of inhabiting another person's perspective. A separate 2013 study in Science tested whether reading fiction made people better at reading emotions from someone's eyes. Across five experiments, people who had just read a short story scored higher on a standard test of emotional perception than people who had read nonfiction or popular fiction. The effect was immediate. The two studies together say something simple: spending time inside a made-up person's head makes you better at understanding the people around you, and the change is not a feeling. It shows up in a brain scanner and on a test. pubmed.ncbi.nlm.nih.gov/2398…