Naturally, the peer group has great power over what you believe about yourself. "If other kids are calling you names and don't want you on their teams, you pick it up with lightning speed," says Nolen-Hoeksema. I was consistently the last one chosen for volleyball, and to this day I regard myself as a person with zero athletic prowess. I always seem to be the least graceful person in yoga class (yes, I know yoga is not supposed to be a competition, but really, people), and I almost wept with gratitude when someone in a jazz dance class told me I moved well. I carry that clumsy little girl I used to be like a monkey on my back, partly because I am what Nolen-Hoeksema has identified as a "ruminator," someone who mulls, analyzes, worries about past, present, and future (the word derives from the Latin for cows "chewing their cud"). If you're a ruminator (and the tendency is there fairly early in life, getting back to that identity card you're issued at birth), when you enter challenging emotional situations, you're more at risk for taking in negative messages—from family, school, the world—essentially turning them on yourself, building a big file of evidence that you really are a screw-up or that people don't like you. "Being a ruminator makes this stuff stick," she says. "But it is changeable. What cognitive therapy seems to do is not convince you otherwise but teach that you can look for alternative ways of viewing yourself. You say, "I know this bad stuff feels like it's true, but it tears me down." And you make the choice to think otherwise."
The most powerful messages are the most global—you feel "ugly" or "fat" or "stupid" or "not good enough"—and they're hard to deflect in adolescence, when you're not sophisticated enough to say: "That's one person's view, and it needn't stick with me." Kids can be remarkably intuitive about the need to protect themselves from negative feedback—remember that childhood chant "Sticks and stones may break my bones, but names will never hurt me." But such an incantation is protective only if the child really believes it. And it's easier to believe the bad stuff when you're unhappy or nervous—a phenomenon known as memory bias. "Our moods shape our ability to recall things about ourselves," explains University of Toronto psychotherapist Zindel Segal, PhD. "Naturally, when you're feeling down, it's easier to recall failures or times when you've messed up. The mind is mired in a negative view. The same holds true for anxiety: Someone who is timid or frightened might be leery of a new situation, might look for comfort in ways she's been able to secure it before. It's staying with the devil you know."