It scarcely matters what it is – tying nautical knots or throwing pottery. Learning something new and challenging, particularly with a group, has proven benefits for the “novelty-seeking machine” that is the brain. Because novelty itself seems to trigger learning, learning various new things at once might be even better. A study that had adults aged 58 to 86 simultaneously take multiple classes – ranging from Spanish to music composition to painting – found that after just a few months, the learners had improved not only at Spanish or painting, but on a battery of cognitive tests. They’d rolled back the odometers in their brains by some 30 years, doing better on the tests than a control group who took no classes.They’d changed in other ways, too: they felt more confident, they were pleasantly surprised by their work, and they kept getting together after the study ended.Skill learning seems to be additive; it’s not only about the skill. A study that looked at young children who had taken swimming lessons found benefits beyond swimming. The swimmers were better at a number of other physical tests, such as grasping or hand-eye coordination, than non-swimmers. They also did better on reading and mathematical reasoning tests than non-swimmers, even accounting for factors such as socio-economic status.Many of these studies or recommendations are oriented toward children. Chess, for example, is held up as a way to improve children’s focus and concentration, to strengthen their problem-solving skills, to bolster their creative thinking. But I’ve become convinced that whenever something is touted as being good for children, it’s even better for adults, in part because we assume we no longer need all those benefits an activity is said to provide.And yet what better remedy for the widespread affliction of “smartphone addiction” than two hours of burning your eyes and brain into 64 squares on a board, trying to analyse an almost infinite variety of moves and countermoves?Learning new skills also changes the way you think, or the way you see the world. Learning to sing changes the way you listen to music, while learning to draw is a striking tutorial on the human visual system. Learning to weld is a crash course in physics and metallurgy. You learn to surf and suddenly you find yourself interested in tide tables and storm systems and the hydrodynamics of waves. Your world got bigger because you did.