During his

press conference following the Boston Marathon bombings, President Obama denounced the perpetrators as "evil" and "cowardly," contrasting their behavior with the heroic first responders who rushed to aid the
injured: "What the world saw yesterday in the immediate aftermath of the explosions were stories of heroism and kindness and generosity and love." He
praised the "good people of Boston" as well as the virtues of the American spirit: "If you want to know who we are, who America is, how we respond to evil,
that's it: selflessly, compassionately, unafraid."

The unity we presently feel doesn't represent a kind of self-deception. Splitting under these horrific conditions allows us to weather the immediate trauma.

Obama's words echo those of George W. Bush speaking on September 11, 2001: "Today, our nation saw evil, the very
worst of human nature, and we responded with the best of America, with the daring of our rescue workers, with the caring for strangers and neighbors who
came to give blood and help in any way they could." In the face of a grave external threat, our leaders rush to offer us the same assurance: we may have
been confronted by "the worst of human nature," but Americans embody its finest virtues.

We
are the heroes, they are the cowards.

We
are motivated by love, kindness and generosity; they feel nothing but hatred.

We
are good, they personify evil.

Leaders in other countries no doubt rely on similar language to comfort their people when facing an existential threat. It encourages unity on the home
front and inspires patriotic feeling. It identifies the domestic goodness worth defending and mobilizes aggression against the enemy. While personal or
political squabbling might dominate during times of peace, we put our differences aside when we face an external enemy. Praising the citizenry of Boston
yesterday on MSNBC, Governor Deval Patrick said that "there's something about America that causes us to come together" at times like this. True, but
citizens in many other nations "come together" in the same way when facing a crisis.

During wartime, or in the immediate aftermath of a terrorist attack, the normally complex world becomes much simpler for most people, wherever they live:
it's good-versus-evil, us against them.

A view of reality that reflects sharp divisions between good and bad, with feelings of love and generosity on one side and hatred on the other, relies upon
the psychological defense mechanism known as splitting. Splitting
normally works to resolve unbearable ambiguity: when we feel unable to tolerate the tension aroused by complexity, we "resolve" that complexity by
splitting it into two simplified and opposing parts, usually aligning ourselves with one of them and rejecting the other. The result is the kind of
black-and-white thinking that underlies the fundamentalist world view or extreme political partisanship.

On the emotional front, splitting comes into play when we feel hostile toward the people we love. Holding onto feelings of love in the presence of anger
and even hatred is a difficult thing for most of us to do. Sometimes hatred proves so powerful that it overwhelms and eclipses love, bringing the
relationship to an end. More often we repress awareness of our hostile feelings; or we might split them off and direct them elsewhere, away from the people
we care about. At one time or another, each of us relies on splitting to some degree. It's built into us, a part of human nature.

Taking refuge in such a belief assuages our fears and inspires confidence about what lies ahead.

Following a traumatic event such as 9/11 or the Boston Marathon bombings, splitting can provide emotional comfort. There's something profoundly appealing
about the belief that we're an inherently good people and that evil (hatred, envy, violence) is not an innate part of human nature but resides "out there,"
in other people. Taking refuge in such a belief assuages our fears and inspires confidence about what lies ahead: after all, we are the good guys, and
don't the good guys always vanquish the bad ones?

Interpreting our experience as a conflict between heroes and villains makes life resemble a work of fiction, a sentimental film of the type churned out by
Hollywood studios during World War II. Movies that invite us to boo the villain and applaud the hero rely on splitting. They have enormous emotional
appeal, in large part because they simplify a complex reality, reducing challenging ambiguity to black and white.

Instead of portraying the conflict of emotions inherent in all human relationships, such movies restrict love, compassion and generosity to their heroes
and paint their villains with a broad black brush. By cheering on the good guys, we (the audience) identify with their goodness, believing our emotional
support proves that we are good people, too. The appeal of such films is obvious; they often succeed in evoking the predictable teary-eyed response even
when we know we're being manipulated. We often want to be manipulated.

In times of fear and stress, we welcome the kind of speeches delivered by Presidents Bush and Obama because we find them comforting, even if we might
consider them sentimental under less traumatic conditions. Today, when the surviving terrorist-brother has only just been apprehended, when families are
still grieving for those who died or were injured by the Boston Marathon bombings, most of us accept

Secretary of State Kerrey's view

that these events constitute "a pretty direct confrontation with evil." We tend to forget the irritations and resentments that might have preoccupied us
just last week, feeling solidarity with our fellow Americans. At least for now, it's us-versus-them.

Of course, we're not as uniformly good as we like to feel; the Tsarnaev brothers, though undoubtedly dangerous, will probably turn out to be confused young
men escaping alienation, shame and a sense of inferiority via
identification with a politically violent cause. This conviction of our own goodness is not hypocrisy, however; the unity we presently feel doesn't
represent a kind of self-deception. Splitting under these horrific conditions allows us to weather the immediate trauma. Not all psychological defense
mechanisms are pathological. Sometimes they're simply necessary to cope with overwhelming pain.

In a month or two once the fear has abated, most of us will relinquish splitting. We'll abandon black-and-white and return to the land of gray. The
emotional sense of unity will inevitably abate and instead of hating those evil terrorists, we'll go back to bickering.