But today, such community intimacy seems part of the past. In a culture where we can pull money from a machine and never interact with a human bank teller, enter a crowded subway without meeting another's eyes, and call telephone assistance only to get information from a computerized voice, it's truly possible to be alone in a crowd.

A blend of social trends has led to this hermit's lifestyle: mass flight from rural areas to the cities and suburbs; the advent of depersonalizing technology at home and at work; and the breakdown of the family, through divorce and career moves. Census figures show that more than 75 percent of Americans now live in cities and suburbs, while national surveys find that a quarter of Americans say they've felt lonely in the last month.

Psychologists are examining this uniquely modern problem, looking at the effects of isolation and technology's role in it (see sidebar on page 46), and developing theories on the psychosocial damage that such alienation can inflict.

While social isolation is in part the product of nonhuman forces such as technology and industrialization, social psychologists emphasize the human dimensions of the problem. In particular, they cite the country's social mobility as a prime reason for increased separation in our culture.

'Compared to most other societies, our bonds are much more tentative and fragile,' says Roy Baumeister, PhD, professor of psychology and an E.B. Smith professor in liberal arts at Case Western Reserve University.

'We can get out of almost any relationship, and the possibility of moving away, changing jobs and losing touch with everyone we once lived with is much more common than it used to be.'

Frequent change of dwelling place 'puts a lot of pressure on the individual to be the 'right kind of person,'' adds Mark Leary, PhD, a psychology professor at Wake Forest University. 'Every time you move to a new place and start a new job, you have to re-establish your identity again.'

The pressure of that dynamic can easily lead to social isolation. It is anxiety-provoking to adapt continuously to new situations, so people don't try as hard to reach out, says Mihaly Csikszentmihalyi, PhD, a University of Chicago psychology professor. Csizszentmihalyi has conducted numerous studies on enhancing use of one's free time and the effects of culture on daily life. He has written a number of popular books on his research, including Flow: The Psychology of Optimal Experience, on tapping the positive aspects of human potential.

In life-enhancement workshops he conducts with middle-aged businessmen, Csizszentmihalyi hears complaints that they have no friends and that because everyone moves in different directions, they have no chance to establish connections, he said.

In addition, beginning with Stanley Milgram, PhD, in the 1970s, social psychologists have long noted the phenomenon that living in crowded areas can 'produce a kind of sensory and cognitive overload and causes [people] to withdraw,' Leary said.

Certain people tend to be lonelier and hence more prone to isolation than others, psychologists have also found. About 2 percent of people are 'social phobics,' who 'are so nervous about social interactions that they live relatively isolated lives and are unhappy in that isolation,' Leary said. People who tend to be rejected by others, beginning in childhood, are also more likely to experience isolation.

Studies by University of Tennessee psychologist Warren Jones, PhD, find that college students-who 'live in an environment full of attractive, intelligent, pleasant people with whom to associate'-are among the loneliest members of society. The reasons are twofold, Jones believes: They tend to be overly idealistic, expecting too much from potential mates and friends. And they reject possible friends and partners because they're 'overcome with their own social anxiety and fear of rejection, and rationalize that fear by saying their friends aren't good enough, attractive enough and so on.'

Whatever its etiology, Baumeister and Leary stress that emotional and social isolation cuts into a basic human drive: the need to belong. In an article published in the May American Psychologist, the two review a wide range of psychological literature to argue that 'belonging' is a fundamental human motivation.

They conclude that the need to belong is probably an evolutionary strategy that fits people's survival and reproductive needs. For instance, children who stay with adults stand a better chance of surviving to adolescence because they'll be better protected and cared for. Likewise, adults who form bonds with both members of their peer group and with a romantic partner are more likely to have children and to add to community life than those who don't, they note.

The need to belong has two major components, both supported by a wealth of research, Leary and Baumeister note. People need frequent personal contacts with others. They also need an interpersonal bond marked by stability, emotional concern and continuity.

The need for both aspects is pronounced in situations where only one is present. In 'commuter marriages,' for instance, the second dimension of caring and stability is present, but not the frequent personal contact. Both partners feel stressed, even though they report they don't doubt each other's love, he says.

'Just having the other person there seems tremendously powerful,' Baumeister says. Likewise, having frequent personal contact but a dearth of emotional bonding-as in the case of a prostitute and his or her client-is unsatisfying, he believes.

So when a culture pushes some of its citizens toward isolation, Baumeister believes 'it goes against human nature' in the most profound sense. 'The data on happiness are pretty clear: People who live in social isolation are very rarely happy.'

Seclusion: as harmful as smoking

In reviewing a decade of literature on social support, University of Michigan sociologist James House, PhD, found that the effects of social isolation on health are as great as the health effects of such factors as cigarette smoking,obesity and high-blood pressure. More strikingly, even, those with a low quantity and quality of social relationships die earlier than others, House found.

Psychologist-researcher Janice Kiecolt-Glaser, PhD, has found that lonely people are more likely to have problems in immune functioning than others. In a 1992 study of 48 adults, she found that those who reported lower social support had a weaker immune response to a hepatitis-B vaccine than others. Her findings ran along a continuum: The less social support subjects reported, the weaker their immune response.

In another recent study, Kiecolt-Glaser tested natural-killer cell activity-which shows how well the body is fighting infection-in 75 medical students a month before they took a final exam, the day of the exam and again when the students returned for vacation. All the students experienced a drop in killer-cell activity during the examinations, Kiecolt-Glaser found. But students who reported that they were lonely had significantly lower levels than others.

Recent qualitative research by Kipling Williams, PhD, suggests that social ostracism can have serious psychosocial consequences (see accompanying article). Subjects he interviewed who were long-term sufferers of ostracism blamed a range of devastating outcomes on the experience of being shunned, including anorexia, suicidal feelings and prostitution.

Even criminal activity may be affected by a lack of belonging, according to research by sociologist Robert Sampson, PhD and criminal justice expert John Laub, PhD. In a 1993 study, the team found that having a good marriage and stable job had a strong deterrent effect on adult crime-suggesting that the obverse may foster criminal behavior.

Fortunately, people have many ways of coping with alienation, from attending church to joining the local baseball team, said Leary.

'Research on patterns of churchgoing suggest it's the social opportunities-the pancake suppers, the youth groups-that really keep people coming back,' he said.

And in an age when fewer people are attending church and joining other traditional institutions, support groups, book clubs and even aerobics classes have become sources of camaraderie, he said.

The adage 'no man is an island' rings especially true in the 1990s when social conditions are leading to a greater possibility of isolation for more people, Baumeister said.

Without meaningful relationships, 'even if a person has enough food, enough money, freedom, all the things they needed to read and be stimulated by-TV and so on-they still wouldn't be happy,' he said.