The world is made up of introverts and extroverts, but even a showman like Bono seeks solitude to compose his lyrics. Stephane De Sakutin / Agence France-Presse - Getty Images

Liberals and conservatives. Believers and nonbelievers. Early birds and night owls.

They all cause one another headaches. Yet one of the most pervasive sources of human frustration is sometimes overlooked: the wall of misunderstanding separating introverts and extroverts.

As Sartre said, "Hell is other people at breakfast."

Unless your vision of hell is eating with someone so lost in his own thoughts that the conversation sputters and dies.

Nevertheless, the consensus seems to be that introverts are shortchanged in societies that reward outgoing, voluble and bossy extroverts. At least if the introverts - who tend to channel their inner laments into articles and books - are to be believed.

Jonathan Rauch warned extroverts in the Atlantic Monthly: "Someone you know, respect, and interact with every day is an introvert, and you are probably driving this person nuts."

Susan Cain, in her book "Quiet: The Power of Introverts in a World That Can't Stop Talking," even blamed the dominance, risk-taking and mindless actions of extroverts for bringing down the global finance system in 2008.

Writing in The Times, Ms. Cain argued that, all too often, shyness and introspection are treated as social disorders: "Studies show that we rank fast and frequent talkers as more competent, likable and even smarter than slow ones." Even though, as the science writer Winifred Gallagher pointed out, "neither E = mc2 nor 'Paradise Lost' was dashed off by a party animal."

But try to imagine a world without irrepressible extroverts like Bono, Bill Clinton and Steve Jobs, inspiring, entertaining and simply getting things done (even if it takes a bit of bossiness mixed in with the nonstop talking jags).

Animal research shows that our evolutionary forebears reveal a balance of personality traits. As Natalie Angier wrote in The Times, "Highly sensitive, arty-type humans have a lot in common with squealing pigs and twitchy mice."

Among pumpkinseed sunfish, there are bold "rovers" and anxious "sitters." David Sloan Wilson, an evolutionary biologist at the State University of New York at Binghamton, told The Times that the rovers sometimes get to food faster, but the cautious sitters are more likely to avoid nets.

In nature, Professor Wilson wrote, "There is no single best personality, but rather a diversity of personalities maintained by natural selection."

Meanwhile, many individuals balance personality traits. The ever-garrulous Bono must seek solitude to write his lyrics. But the "quiet" Beatle, George Harrison, also had a wild side.

Despite the inherent tensions between the two types, there are indications that the introvert-extrovert schism can be bridged. As The Times reported, one of the factors contributing to the general failure of many online dating services is that their algorithms seek to match extroverts with extroverts, introverts with introverts.

But such characteristics rarely predict the success of a relationship. A survey of more than 23,000 married couples in 2010 revealed that in unions between different personality types, such variations accounted for only 0.5 percent of what made couples happy or unhappy.

The same probably cannot be said about marriages between liberals and conservatives, believers and nonbelievers or early risers and late sleepers.

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(China Daily 03/11/2012 page9)