The Defining Decade: Why Your Twenties Matter—And How to Make the Most of Them Now

by Meg Jay

Evolutionary theorists believe the brain is designed to pay special attention to what catches us off-guard, so we can be better prepared to meet the world next time. The brain even has a built-in novelty detector, a part that sends chemical signals to stimulate memory when new and different things happen.

when research subjects are startled, such as by the image and sound of a snake, they have better recall for the slides that immediately follow the snake than they do for other slides. Similarly, people are more likely to remember highly emotional events, such as times when they were happy or sad or embarrassed.

When something surprising happens, especially if it arouses emotions, we tend to remember it—vividly—for a long time. These remembrances are called flashbulb memories because they feel illuminated and frozen in time, like our brain has taken a photograph of the moment.

Twentysomethings take these difficult moments particularly hard. Compared to older adults, they find negative information—the bad news—more memorable than positive information—or the good news. MRI studies show that twentysomething brains simply react more strongly to negative information than do the brains of older adults. There is more activity in the amygdala—the seat of the emotional brain.

With age comes what is known as a positivity effect. We become more interested in positive information, and our brains react less strongly to what negative information we do encounter.

When Danielle called her mother, she was doing what psychologists call “borrowing an ego.” She was reaching out in a moment of need and letting someone else’s frontal lobe do the work.

Inaction breeds fear and doubt. Action breeds confidence and courage. If you want to conquer fear, do not sit home and think about it. Go out and get busy. —Dale Carnegie, writer and lecturer

Rather than strengthening their skills and toughening their resolve, four years of college left the students with fixed mindsets feeling less confident. The feelings they most associated with school were distress, shame, and upset. Those with growth mindsets performed better in school overall and, at graduation time, they reported feeling confident, determined, enthusiastic, inspired, and strong.

Real confidence comes from mastery experiences, which are actual, lived moments of success, especially when things seem difficult.

A more resilient confidence comes from succeeding—and from surviving some failures.

Goals are how we declare who we are and who we want to be. They are how we structure our years and our lives. Goals have been called the building blocks of adult personality,

entering into stable relationships helps twentysomethings feel more secure and responsible, whether these relationships last or not. Steady relationships reduce social anxiety and depression as they help us feel less lonely and give us the opportunity to practice our interpersonal skills.

A 2010 report by the Pew Research Center titled “The New Demography of American Motherhood” shows that today’s mother is older and more educated than the mothers of the past. Babies born to mothers over thirty-five now outnumber those born to teen moms, and the average age for first-time motherhood is twenty-five, with about one-third of first-time moms over thirty. The number of women who opt for childbearing between the ages of thirty-five and thirty-nine has increased by nearly 50 percent in the last twenty years, and by 80 percent for women aged forty to forty-four.

Researchers are beginning to find that older sperm may be associated with various neurocognitive problems in children, including autism, schizophrenia, dyslexia, and lower intelligence.

The availability heuristic is a mental shortcut whereby we decide how likely something is based on how easy it is to bring an example to mind.

Past age thirty-five, intrauterine insemination—or the “turkey baster method” in which sperm is inserted into the female reproductive tract—has a 90 to 95 percent failure rate. In vitro fertilization—“IVF” or “in vitro,” when sperm and egg are united outside the body and implanted in the uterus—succeeds only about 10 to 20 percent of the time. In older women, the failure rate for these procedures is so high, many fertility clinics will not perform them on fortysomething women at all.

a 2010 study shows that simply postponing marriage and children leads to more stressful lives for families.

According to the parents surveyed, about half feel they have too little time with their youngest child, about two-thirds feel they have too little time with their spouse, and another two-thirds report too little time for themselves.

Men and women will soon face caring for two entirely dependent groups of loved ones at precisely the moment they are most needed back at work.

This study brings to life, at least digitally, a core problem in behavior: present bias. People of all ages and walks of life discount the future, favoring the rewards of today over the rewards of tomorrow.

The future isn’t written in the stars. There are no guarantees. So claim your adulthood. Be intentional. Get to work. Pick your family. Do the math. Make your own certainty. Don’t be defined by what you didn’t know or didn’t do. You are deciding your life right now.