The world's first Global Family Reunion will be June 6 in New York City. The invitation list runs to 7 billion people: Earth's entire population.
So far, 77 million of them have a proven connection to the world's biggest family tree, created by A. J. Jacobs, the reunion's mastermind, who is fascinated that many millions of people can find familial connections to many millions of other people, past and present.
You're a cousin, so you're welcome to attend.
As it happens, Jacobs is a pretty close cousin of mine. He's my father's sister's grandson. Because of this and because he knows his own family tree, he can show my connection to lots of people. Frank Sinatra, it turns out, is a very distant cousin (by marriage -- many marriages, actually).
Abraham Lincoln is a distant cousin, too. And, of course, Lady Gaga. It turns out that radio host Glenn Beck -- who has called me "the most dangerous man in America" and also "the most evil" -- is a cousin as well.
Welcome to the family, Glenn! People are intrigued by links of this kind, and I think I know why. To borrow a term from behavioral science, Jacobs is using a "heuristic," which means a mental shortcut, or rule of thumb, which generally works well but also tends to go wrong. More specifically, Jacobs is using a brand-new heuristic, which deserves its own name: the "family heuristic." Here's how it works: Most of us feel a commonality with members of our family. At least in general, we treat them with familiarity and kindness. We sacrifice for them. We welcome them. We laugh with them. We are gentle with them; we give them the benefit of the doubt.
To qualify as a member of your "family," of course, a person must usually be part of a relatively small group -- your parents, siblings, children, aunts and uncles, in-laws, first cousins, and those with a close relationship to any of the above. But modern genealogical tools make it easy to show that the universe of familial connections is extraordinarily large.
Jacobs is exploiting the family heuristic by triggering the positive emotions and the strong feelings of commonality associated with small kinship units and applying them to the big world of distant strangers.
We might then conclude that, used in this way, the family heuristic is a bit of a parlor trick, and it goes terribly wrong, because the relevant emotions are usually triggered by, and most suitable for, close relations. But consider another possibility: Whenever you're irritated by strangers on the subway, or enraged by people of the opposing political party, or whenever you wonder whether it's really worthwhile to help vulnerable people who are far away, it might not be a bad idea to consider that they, too, might be your cousins.
Maybe the family heuristic doesn't go wrong at all.
Cass R. Sunstein, a Bloomberg View columnist, is Frank's ex-wife's ex-husband's ex-wife's ex-husband's second cousin once-removed's husband's first cousin twice removed.