主题：【文摘】Time上的一篇文章 -- 闲看蚂蚁上树

If siblings can indeed be as powerful an influence on one another as all the research suggests, are all siblings created at least potentially equal? What about half-sibs and stepsibs? Do they reap--and confer--the same benefits? Research findings are a bit scattered on this, if only because shared or reconstituted families can be so complicated. A dysfunctional home in which parents and siblings hunker behind barricades alongside the ones they're biologically closest to does not lend itself to good sibling ties. Well-blended families, on the other hand, may produce step- or half-siblings who are extraordinarily close. One of the best studies on this topic is being conducted in Britain with a large group of many different kinds of nontraditional families. In general, the researchers have found that the intensity of the relationships closely follows the degree of physical relatedness. No hard rules have emerged, but the more genes you share, the more deeply invested you tend to grow. "Biological siblings just get into it more," says Thomas O'Connor, an associate professor of psychiatry at the University of Rochester Medical Center. "They are warmer and also more conflicted."

• How those early bonds can grow stronger with age

ONE OF THE GREATEST GIFTS OF THE SIBLING tie is that while warmth grows over time, the conflicts often fade. After the shooting stops, even the fiercest sibling wars leave little lasting damage. Indeed, siblings who battled a lot as kids may become closer as adults--and more emotionally skilled too, often clearly recalling what their long-ago fights were about and the lessons they took from them. "I'm very sensitized to the fact that it's important to listen to others," a respondent wrote in a recent study conducted in Britain. "People get over their anger, and people who disagree are not terrible," wrote another. Even those with troubled or self-destructive siblings came away with something valuable: they learned patience, acceptance and cautionary lessons. "[You] cannot change others," wrote one. "[But] I wasn't going to be like that."

Full-blown childhood crises may forge even stronger lifelong links. The death of a parent blows some families to bits. But when older sibs step in to help raise younger ones, the dual role of contemporary and caretaker can lay the foundation for an indestructible closeness later on. Wayne Duvall, 48, a television and film actor in New York City and the youngest of three brothers, was just 13 when his father died. His older brothers, who had let him get away with all manner of mischief when both parents were in residence, intuitively knew that the family no longer had that luxury. "I vividly remember them leaning down to me and saying, 'The party's over,'" Duvall recalls. "My brothers are my best friends now, though they still consider me the little brother in every imaginable way."

Such powerful connections become even more important as the inevitable illnesses or widowhood of late life lead us to lean on the people we've known the longest. Even siblings who drift apart in their middle years tend to drift back together as they age. "The relationship is especially strong between sisters," who are more likely to be predeceased by their spouses than brothers are, says Judy Dunn, a developmental psychologist at London's Kings College. "When asked what contributes to the importance of the relationship now, they say it's the shared early childhood experiences, which cast a long shadow for all of us."

Of course, that shadow--like all shadows--is a thing created by light. Siblings, by any measure, are one of nature's better brainstorms, and all the new studies on how they make us who we are is one of science's. But the rest of us, outside the lab, see it in a more primal way. In a world that's too big, too scary and too often too lonely, we come to realize that there's nothing like having a band of brothers--and sisters--to venture out with you.

See what famous siblings have said about one another at time.com/siblings

With reporting by With reporting by Jessica Carsen/London, Wendy Cole/Chicago, Sonja Steptoe/Los Angeles