It took Barbara Hustedt Crook an awfully long time to get around to writing her first musical. She started last year, shortly before her 60th birthday. Her friend and collaborator, Robert Strozier, waited even longer; he’s 65. It’s not that they didn’t have the creative chops for the job. The two have spent their careers writing and editing in New York City, and Crook has a background in performing, singing and piano. But creating a musical always felt just out of reach–until now. “Somehow I have a confidence I didn’t have before,” says Crook. “I find that my brain makes leaps it didn’t make so easily. I can hear my inner voice and trust instincts and hunches in ways I didn’t used to.” And, says Strozier, they’re both a lot more willing to take chances than in the past. “At a certain age,” he says, “you either get older or you get younger. If you get younger, you venture out and take risks.” Risk-taking seniors making daring mental leaps? That’s not the stereotype. Indeed, until quite recently most researchers believed the human brain followed a fairly predictable developmental arc. It started out protean, gained shape and intellectual muscle as it matured, and reached its peak of power and nimbleness by age 40. After that, the brain began a slow decline, clouding up little by little until, by age 60 or 70, it had lost much of its ability to retain new information and was fumbling with what it had. But that was all right because late-life crankiness had by then made us largely resistant to new ideas anyway. That, as it turns out, is hooey. More and more, neurologists and psychologists are coming to the conclusion that the brain at midlife–a period increasingly defined as the years from 35 to 65 and even beyond–is a much more elastic, much more supple thing than anyone ever realized. Far from slowly powering down, the brain as it ages begins bringing new cognitive systems on line and cross-indexing existing ones in ways it never did before. You may not pack so much raw data into memory as you could when you were cramming for college finals, and your short-term memory may not be what it was, but you manage information and parse meanings that were entirely beyond you when you were younger. What’s more, your temperament changes to suit those new skills, growing more comfortable with ambiguity and less susceptible to frustration or irritation. Although inflexibility, confusion and even later-life dementia are very real problems, for many people the aging process not only does not batter the brain, it actually makes it better. “In midlife,” says UCLA neurologist George Bartzokis, “you’re beginning to maximize the ability to use the entirety of the information in your brain on an everyday, ongoing, second-to-second basis. Biologically, that’s what wisdom is.”