"Identity" — having a strong sense of self and feeling you know who you are and what you want out of life — also increased over time. "And it doesn’t stop," Whitbourne notes.Of course, generalities never give a complete picture, as all the researchers I spoke with pointed out. Midlife, they emphasized, varies for different people at different times and in different places. Indeed, the very years that constitute middle age change depending on whom you ask. I, for example, don’t plan to slip into — what’s it called now? the "young old"? — until I’m 70.But patterns do matter. They give us a foundation, a way to fit ourselves into the world. The midlife confidence surge, I’m now convinced, is as real as the sweat dripping off my face as I drive home from Amherst, hot but happy, in my un-air-conditioned Volvo.Six weeks later, I practice some mindful breathing before stepping into the dance studio — 2,500 square feet of light and air. From my position in the back, the 10-foot-high front wall of mirrors reflects not so much the bodies in the room but the great outdoors — leafy treetops, blue sky — shining through the giant windows behind us."Pull in your ribs, drop your pelvis, align your hips, stand on the inside of both legs," choreographer Dan Wagoner, himself a spry 75, cajoles us, using his hands to align his own body to illustrate what goes where. "Be of one piece.""That’s it, dancers!" he exclaims. "Ah, when you have children they will drop right out of you!"At 54, I am well past the age of having children drop right out of me. But I am lifted and expansive, right where the researchers say I’m expected to be at this point in my life: I’m ready to fly.This Is Your Brain on ConfidenceMedical experts tell us that gray matter — the billions of neurons in the brain that process information — starts shrinking in our early teens. What we hear less often is the good news: that white matter — the insulated nerve fibers that connect the neurons and enable them to function at top speed and efficiency — keeps growing until we die. Studies by UCLA neurologist George Bartzokis, MD, have found that white matter volume reaches its peak in middle age — from 45 to 55 or 60, depending on the brain region. Both women and men enjoy this midlife brain perk; where some researchers say the genders differ is in brain "laterality." "Women tend to use both sides of their brain for processing, whereas men tend to use one side or the other," says Cynthia Darlington, associate professor at the University of Otago, in New Zealand, and author of The Female Brain. "This means that many women can parallel process — that is, process a couple of trains of thought or activities at once." Leanne M. Williams, director of the Brain Dynamics Centre at the Westmead Millennium Institute in Sydney, Australia, recently made another midlife-brain discovery. Over the years, her studies show, the brains of both sexes get better at suppressing negative emotions and letting positive ones through — but women’s scores seem to outpace men’s. Neuroticism in women declined, too. "Women are the ones whose brains are the most emotionally stable," Williams says, "particularly from age 50 on." Memo to Dr. Freud: Yes, anatomy is destiny, but not in the way you had in mind.Originally published in MORE magazine, February 2008.