Is there someone in your life whom you would feel comfortable phoning at four in the morning to tell your troubles to?

If your answer is yes, you will likely live longer than someone whose answer is no. For George Vaillant, the Harvard psychiatrist who discovered this fact, the master strength is the capacity to be loved. Conversely, as the social neuroscientist John Cacioppo has argued, loneliness is such a disabling condition that it compels the belief that the pursuit of relationships is a rock-bottom fundamental to human well-being.

I always wonder about the validity of these types of longevity "markers."  What happened to the anecdotal old, long-living grump?