While humans are bred to fight, they are also wired by evolution to cooperate with and get support from each other. These close ties also get us through economic and personal crises. We need people to turn to when we learn we have cancer, have lost our job, or our marriage is crumbling. In friends and family, we hone our social capital skills, by tempering our selfinterest for the larger, longer-term interests of family or friendship. Moreover, close ties can provide important venues in which we can discuss civic or political topics like religion, happenings in our communities, the country or the world, or political issues.

What has happened to our close ties? More than one-fourth of American households (29.8 million of them) consist of just one person, compared with less than one-fifth of American households (13.9 million) in 1975.18 A recent Duke University study by Miller McPherson, Lynn Smith-Lovin, and Matthew E. Brashears revealed that Americans have smaller circles of people with whom they can discuss important matters than they did even as recently as 1979. About one in four Americans has no one with whom to talk about weighty matters, and nearly half of the population is one close friend or family member away from being socially isolated.19

The measures that McPherson and colleagues used were only collected twice. For our Index, we include regular annual survey questions about eating dinner with one’s family and visiting friends. Family dining shows the steepest decline, while the rate at which people visit their friends is more stable. “Online chat” rooms or forums have risen rapidly in recent years, but the large increase in 2005 does not affect the Index, which stops at 2004. The chart above shows some leveling off in the last 10-12 years.