FOR as long as humans have gathered in groups, it seems, some people have been left on the outside looking in. In postwar America in particular, the idea that loneliness pervades a portion of society has been a near-constant. Only the descriptions have changed: the "lonely crowd" alienation of the 1950's; the grim career-driven angst of the 70's and 80's; the "Bowling Alone" collapse of social connections of the 90's.

There is a new installment in the annals of loneliness. Americans are not only lacking in bowling partners, now they're lacking in people to tell their deepest, darkest secrets. They've hunkered down even more, their inner circle often contracting until it includes only family, only a spouse or, at worst, no one.

And that is something the Internet may help ease, but is unlikely to cure.

A recent study by sociologists at Duke and the University of Arizona found that, on average, most adults only have two people they can talk to about the most important subjects in their lives — serious health problems, for example, or issues like who will care for their children should they die. And about one-quarter have no close confidants at all.

"The kinds of connections we studied are the kinds of people you call on for social support, for real concrete help when you need it," said Lynn Smith-Lovin, a sociologist at Duke and an author of the study, which analyzed responses in interviews that mirrored a survey from 1985. "These are the tightest inner circle."

The study "should provide a wake-up call to our society," said Bill Maier, a vice president and psychologist in residence with Focus on the Family, the evangelical Christian group. "We're missing out on deep, meaningful interpersonal relationships."

Yet within the analysis there was at least a suggestion of hope.

"The one type of relationship that actually went up was talking over personally important things with your spouse," Dr. Smith-Lovin said.

Like "Bowling Alone," the essay and, later, book by Robert D. Putnam, a public policy professor a Harvard, the Duke study suggested that a weakening of community connections is in part responsible for increasing social isolation. More people are working and commuting longer hours and have little time for the kinds of external social activities that could lead to deeper relationships.

So the closest ties increasingly are limited to family members, in particular to spouses.

"That's probably a result of the fact that men's and women's lives are more structurally similar now than in 1985," Dr. Smith-Lovin said. It's more likely that both spouses are working at jobs that are important to them, and men are more involved around the house. "Spouses literally have more to talk about," she said.

Dr. Maier, for one, sees that as cause for at least some optimism in a society whose fast pace generally bodes badly for family life. "To hear that people are investing more in their nuclear family is a positive thing," he said.

The Internet is also cause for some optimism, because it has made it easier to maintain ties among family members who have become scattered. Those ties inevitably developed over long-term, face-to-face contact, but e-mail can help keep them strong.

"E-mail really does help maintain your social networks," said John Horrigan, associate director of the Pew Internet and American Life Project. Recent Pew surveys, he said, found that "when you contact family by e-mail, you share important and serious things."

Still, Dr. Smith-Lovin said, any optimism must be tempered. For one thing, having only one confidant, even if that confidant is a spouse, leaves a person extremely vulnerable if the spouse dies or the marriage disintegrates.

And in the end, she and others pointed out, e-mail or instant messaging is no substitute for face-to-face contact. "E-mailing somebody far way is not the same as them going to pick up your child at daycare or bringing you chicken soup," she said.

Dr. Putnam said the new study reinforced much of what he had reported in "Bowling Alone," which had been criticized by some academics as a faulty analysis that ignored other social and economic trends. And even if the new study points to a rise in spouses as confidants, that is not especially cause to rejoice, he said. "It's like with global warming, if we learn that temperatures are going to rise slightly less than we thought," he said. "It's still a problem."

"Sure, you might say, we've still got our wives or husbands or mothers," he said. "That's true. But gosh, the number of friends you have is a strong predictor of how long you live."

The impact goes beyond the individual, as well. "There are effects on my neighbors of my not knowing them," he said. For one thing, "If I don't know them well and they don't know me, that has a demonstrable effect on the crime rate."

Dr. Horrigan said there was anecdotal evidence that some members of a community use e-mail and the Internet "to keep up with people very close by." The Internet can help expand social networks, although the ties it creates are not as strong as those the Duke researchers are concerned with. Yet they can be useful.

His group's research has shown that the Internet is increasingly being used during life's "major moments" — to gather information or advice when making a big financial investment, deciding where to live, or choosing a college for a child. The research has shown that "people were more likely to get help through their social network" for those kinds of decisions.