If you were to track the daily happenings that flatten people's moods, you would likely find rejection at the core. "A very high percentage of negative events are related to the feeling that someone else doesn't value a relationship as much as you do," says Duke University psychologist Mark Leary. Those are the sore feelings that accompany such thoughts as, "Why did my coworker brush me off in that meeting?" or "My husband is watching TV when he should be paying to me!"

The drive to bond lies deep in our . Disappointment when we fail to connect is virtually guaranteed. That's why the ultimate rejection—the departure of a loved one—is among the most of all experiences.

Even the tiniest of slights can rile our emotions and send our into a tailspin. In part, self-esteem reflects who we are intrinsically, but is also a barometer of our standing with others. Leary found that social self-esteem neatly rises with any inkling of acceptance ("Would you like to join us for lunch?") and plummets with any cut-down ("I like you—as a friend!").

"It's an internal gauge that is independently programmed," he explains. "So when you feel bad, you tend to feel bad about yourself." Social self-esteem acts like radar, scanning for any hint of disapproval or exclusion. A blip on the meter, felt as a drop in self-esteem, is unpleasant, designed to spur us to address the source of the discomfort. If the gauge weren't sensitive to all signs of rejection, it might miss the big ones, endangering or even safety. "Nature designed us to be vigilant about potential rejection," says Leary, "because for most of our history we depended on small groups of people. Getting shut out would have compromised survival."

As anyone who has ever watched American Idol knows, sensitivity to rejection exists along a continuum. The clueless party host who spews a string of tasteless jokes, as guests squirm, sits at the low end. At the high end is the vigilant scavenger who finds rejection in every empty inbox and between every ambiguous line. How she perceives and reacts to rejection is instructive for all of us—because we're all moving closer to her end of the continuum. Observers see a wave of psychological fragility pushing individuals in our culture toward oversensitivity to rejection.

A jittery rejection-detection radar zeroes in on empty threats—creating needless anxiety and groundless . Unfortunately, those at the high end of the rejection-sensitivity scale pay a particularly steep price just for wanting to belong. Their overwrought responses to slights may even have the unintended effect of bringing about what they most. And although such pain may be borne privately, it has public repercussions. There is a collective cost of individual hypersensitivity to rejection. People become unwilling to take even the smallest social risks. Preoccupied with their own performance evaluations, people away from approaching strangers or questioning authority. Public life shrinks and civil society withers.

Hypersensitivity Rising

There are a number of reasons why rejection-sensitivity is growing more pervasive. Major , a condition tightly linked to , has been on the rise among all age groups except the elderly for well over a decade. What's more, parents and educators overprotect and over-praise children, actions that backfire because they breed a preoccupation with evaluation by others. "If praise isn't based on anything specific, it gives you a sense of insecurity," Leary points out. "It makes you wonder whether your rejection radar is working at all." If you suspect you're not getting honest feedback, you'll be more sensitive to all possible slights or acceptances. You'll think, "Do people really like me?"

Then, too, adds New York psychologist Robert Leahy, we're on our way to becoming a performance-based culture. Young people in particular feel an urgency to grab the spotlight, instead of working toward becoming a stable member of a group. That makes them especially concerned with how others are evaluating them—and more sensitive to rejection.

But the primary reason we're becoming more rejection-sensitive, Leary contends, is that our fragmented, mobile society has decreased the number and weakened the strength of our social bonds. "Even 200 years ago, people were part of a small clan. They likely lived their entire lives in the same town. We now constantly have to reintegrate ourselves into new social networks. The sheer number of strangers with whom we interact creates many more opportunities for rejection."

Leahy, clinical professor at Weill-Cornell Medical College and author of The Worry Cure, agrees. "Because families are less intact and society is more segmented, we're all less secure. Further, an increased general sense of uncertainty makes us more vulnerable to rejection."

However subtle these background influences are, they all rub up against a stark fact: Our rejection radar is just not adapted to a world in which we're thrown against new and often strange situations daily. If the corner fruit vendor ignores your cheery "good morning!" it doesn't mean he won't sell you an apple; if your coworkers forget to invite you to after-work drinks, you're not necessarily the office pariah. Still, Leary says that he would rather err on the side of over-reading signals of rejection. Imagine if you had no pain receptors to warn you of impending bodily harm—you wouldn't feel scrapes or punches, but you wouldn't survive long, either.

From Fear to Eternity

When starting out as a psychologist, Geraldine Downey, now a professor at Columbia University, sought to discover how children whose early years were marked by parental rejection fared in adult relationships. She hypothesized that those whose needs for care and were repeatedly met with rejection would likely grow up to anticipate it, see it where it might not exist, and overreact to it, as if life itself were on the line. After more than a decade of research, she has unveiled a fairly detailed portrait of people who are highly sensitive to rejection.

Awash in anticipatory anxiety or pre-emptive , they expect to be rejected by those they grow to value. They interpret neutral or negligent actions (a delay in phoning, say) as intentional slights. They are primed to find firm evidence of whatever feels threatening to them, cognitively poised to interpret situations negatively. They don't give anyone the benefit of a doubt. Women are no more likely than men to be overly rejection-sensitive, but does influence the way they react to imagined or actual slights: Men express more jealousy, women become more hostile and unsupportive. To ferret out a person's expectations of rejection, Downey asks questions such as:If you must approach your family for a loan, how would you be? Would you expect them to help you?

Through a set of ingenious studies, Downey has discovered that, just as we have a nervous system that makes us reflexively recoil in self-protection when we spot a snake, we also have a defensive system that tries to protect us from rejection. Automatically triggered by the merest hint of rebuff, it throws our body into physiologic alarm mode, riveting our attention on the need to do something fast and urging us to head off an impending relationship rupture.

Improbably, the finding owes something to artists Edward Hopper and Pierre-Auguste Renoir. Hopper's scenes of urban desolation, Downey observed, are generally perceived as depictions of rejection, while Renoir's soft scenes come across as acceptance. After showing images of paintings by both artists to subjects in her study, she startled them with a loud noise. And then, via eyelid sensors, she counted their eye blinks.

Indeed, those who were highly rejection-sensitive reacted to the Hopper paintings, but not the Renoirs, with an amplified eye blink when startled by the noise—a sign that their bodies and minds had been pitched into panic. The threat of social rejection exaggerated their physiological response. By contrast, those low in rejection-sensitivity reacted equally to the noise whether viewing Hopper or Renoir scenes.

Although the defensive system is designed to motivate relationship repair, it backfires on those who are highly rejection-sensitive. They live life in panic mode, which not only brings them relentless emotional turmoil, but also sets off the most frustrating feature of rejection-sensitivity: It becomes a self-fulfilling prophecy. Magnifying oversights and seeing slipups as proof of catastrophe, they unleash hostility, anger, despondency, or jealousy. Their emotional storms often drive away the very people they hoped to hook.

"It happens in all contexts," says Leary. "A coworker may respond exaggeratedly to a tiny slight, which then leads office mates to avoid her, which makes her more defensive. Or your teenage son may blow you off, which makes you more distant and stern, which makes him shut you out even more."

An Early Start

There's no one path to rejection sensitivity. Clinicians and researchers know that children of emotionally or physically abusive, neglectful, or critical parents tend to become highly sensitive to rebuffs. Also at risk are children who grow up in poverty or war zones, situations that can divert parental attention and undermine formation of secure bonds.

The quality of a child's relationship with parents is hardly the sole determinant of rejection-sensitivity. Also influential is the child's innate level of reactivity to stress. Genetic makeup or premature birth may set the nervous system on the skittish side, making a child hypersensitive to rejection even if parents are not abusive or neglectful. To counteract a riled-up rejection radar, however it gets set, says Downey, a child would need "superparents" attentive to his needs and feelings.

There's some evidence that a heavy dose of peer rejection in can also precipitate rejection-sensitivity. A child who is constantly taunted by peers may, as a young adult, begin to expect rejection from romantic partners and coworkers, in spite of a secure attachment to Mom and Dad.

It's rare for anyone to become rejection-sensitive in adulthood. A young man whose fiancee leaves him may approach dates with wariness, but he wouldn't also expect rejection from everyone he encounters, including friends or coworkers.

Depression and Rejection: Chicken or Egg?

Unsurprisingly, people who are rejection-hypersensitive have lower "trait" self-esteem, the feeling you have about yourself in the absence of any feedback. "You will take rejection personally if you don't think you are particularly valuable to begin with," says Leary. Slights will only confirm your suspicion that you deserve to be left out.

Depressed people are more sensitive to rejection than the nondepressed. Rejection-sensitivity is a hallmark of so-called atypical depression, which is actually the most common type of the disorder. Those with atypical depression uniquely experience a temporary lift in mood when something good happens to them. But they are then more susceptible to feeling down in response to any negative event—and less likely to bounce back quickly.

It's not clear which comes first—depression or rejection-sensitivity. "People who are depressed do tend to get rejected," observes Downey. Even if others understand and know that a person is depressed, it's hard to put up with the irritability, the negativity, and the self-doubt that accompany the condition. Among those who suffer from , interpersonal difficulties and feelings of rejection rise in the winter months when the blues are most acute. And people who score in the red zone of rejection-sensitivity on Downey's test are more likely than others to become clinically depressed in the aftermath of a breakup.

A Fine Line

The difference between a normal response to rebuffs and an oversensitive one may be summed up in one word: rumination. Highly rejection-sensitive people are also more likely to be "overthinkers" who ruminate excessively about everyday experience. Overthinking may be the engine of hypersensitivity to rejection, says Susan Nolen-Hoeksema, professor of psychology at Yale and author of Eating, Drinking, Overthinking. If you begin to dwell on the fact that your friend has not returned your recent e-mail, your brain will run a file search and pull up possible reasons for why she is angry with you and why she may even be on the verge of you out of her life.

As you stew in your negative thoughts, hostility and anxiety rise, all in the absence of any real information about why your pal is incommunicado. Overthinking stirs people who are rejection-sensitive to sabotage themselves. "When you are ruminating, you get immobilized because you discount the effectiveness of taking preventive action," says Nolen-Hoeksema.

Instead of working constructively to repair what may be a severed tie, you build a case for why you've been rejected. And when you do finally see your friend, your emotions will be so disproportionate to any slight that she will likely be annoyed—and yes, perhaps even reject you.

A normal response to intimations of rejection would be some attempt to gather information or move directly into repair mode. But rejection-sensitive souls cling to losing strategies. They might desperately seek out and make unreasonable demands of a partner—appearing overly invested yet anticipating the partner's departure. Or they avoid intimacy altogether—averting stormy relationships but losing out on the chance to find acceptance and support. Either path puts them at risk for and depression.

Eggshell Existence

To say that rejection hurts is not to speak metaphorically. UCLA Naomi Eisenberger and colleagues have found that rejection activates the same brain area that generates the adverse reaction to physical pain, causing a sharp spike of activity in the anterior cingulate. Being ditched by your best friend is as threatening to your well-being as touching a hot stove.

Kids who constantly expect rejection are more aggressive and get into trouble more with teachers than do their classmates. Young adults who are sensitive to rebuffs tend not to open up and reveal themselves in the early stages of . They may have a hard time with transitions and adjusting to new settings. A diary study of college freshman found that rejection-sensitive students made fewer friends and liked school less than did their peers at the end of the year.

Rejection-phobes are also less willing to have friends who are different from themselves—from other ethnic backgrounds, for instance. A tendency to stick to one's own kind could impede young adults from gaining an enriched perspective on life.

Hands down, the rejection-sensitive suffer most in the realm of romance. No matter how committed their partners are, they worry about being dumped. They attribute hostile intent to innocuous behavior. Unsurprisingly, both they and their partners are less happy than other couples.

"Living with someone who is sensitive to rejection is like walking on eggshells," says Leary. "Any little slip up on your part—like calling at 6:03 instead of 6:00—could trigger their anger." They tend to seek constant reassurance from partners, but even if told repeatedly that they are loved, the information isn't trustworthy—because the affirmation had to be elicited. It's maddening for others to deal with. "People who feel secure have a hard time understanding a partner like this," Leary notes.

Still, there are situations that bring out the rejection-phobe in even the sturdiest soul. Starting a new school or moving to a new neighborhood makes everyone vulnerable to self-doubt. And power differentials—say, between boss and employee—attune everyone to the slightest hint of rejection. "I am the department chair," says Downey. "I don't think of myself as being in a position of power, yet I notice that people read more into my behavior. Sometimes I look at my watch during a meeting simply because I'm trying to figure out how much time I have left. But people misinterpret that and , or even get up to leave."

Cushions and Buffers

Dismantling a hypersensitive rejection-detection system is far easier said than done. Asked how becoming a prominent expert on rejection has helped him deal with personal brush-offs, Leary responds with a sigh. "I don't know that it has. But in retrospect, I understand very well what happened after I've overreacted to rejection. I know exactly what went wrong. But it still went wrong." Awareness, though, is the first step in breaking the rejection-sensitivity cycle.

The best remedy for rejection-sensitivity is caring friends who can tolerate defensive antics and engender trust. Downey found that among rejection-sensitive people who did manage to find and keep a loving romantic partner, reactivity abated over time. Perhaps the support of a good person kicks the subversive cycle into reverse mode: The rejection-phobe begins to feel more secure, which paves the way for an even happier relationship, until an empty inbox is no longer a cold reproach or a sign of impending doom—but rather just an empty inbox.