Here's a TED talk by psychiatrist Robert Waldringer, the fourth director of a 75-year-old Harvard longitudinal Study of Adult Development, begun in the '30s, on what keeps us happy and healthy. (Actually, this is a study of what keeps men happy and healthy, just to pick a bone on who gets studied in most research ... but that's a battle for another day.)

The study looked at the lives of 724 men, from their teens into their 90's. Half were Harvard sophomores and half were from Boston's poorest neighborhoods. Sixty of the original men are still alive, most of them in their nineties.

The lessons are simple but of great consequence, and Waldringer does an elegant job of spelling them out.

The bottom line: good relationships have a protective effect on our health, happiness and our brains. Social connections are good for our health. Loneliness is associated with shorter, sicker lives and declining brains. It's not about having money, once a certain threshold of income has been reached. And fame has a negative impact on health.

There is nothing new here that our grandmothers didn't already know, but there's never been such a long term study to show it so well.