America's happiest city? Smile survey says St. Louis

Jayne Clark | USA TODAY

A new city guide iPhone app says it can garner all sorts of information about a place — including the general happiness of its residents — by analyzing millions of photos posted on the social networking site Instagram.

The free Jetpac City Guides app, launching today, undertakes a pixel-by-pixel examination of the contents of millions of photos to convey particulars about restaurants, attractions and more in 5,000 cities. Among the secrets it says it can divine from examining Instagram photos: bars women love, hikes only locals know about and dog-friendly spots.

But more about those happy cities and how Jetpac determines happy places vs. more down-in-the-mouth spots. One word: smiles. In analyzing millions of photos of people in various places, it awards a "smile score" based on the size of the smiles in Instagram photos.

The No. 1 smiling city, according to Jetpac: St. Louis, followed by Kansas City, Mo., and Columbus, Ohio. In fact, seven of the 10 smiling-est cities are in the Midwest, including bankrupt Detroit, at No. 9.

Of the 50 rated cities, dead last in smiles is (irony alert!) Anaheim, Calif., home of Disneyland aka the Happiest Place on Earth. No. 49, (double irony alert) is Paradise, Nev., an unincorporated area of Las Vegas that takes in most of the Strip.

On the state-by-state ranking, the top smile score goes to South Dakota, followed by Montana and North Dakota. Again, Midwesterners appear to have the edge when it comes to happy hormones. Six of the top 10 smile-scoring states are in the heartland.

Jetpac employs a complex algorithm to figure this all out, but I wondered whether it can tell when people are fake smiling for the camera (something I do all the time).

"Well, we're not looking at the eye-crinkle component. But we could," says Jetpac CEO Julian Green, who adds that he believes the most direct measure of happiness is a person's smile.

After all, he quips, "You think people are fake-smiling in Detroit?"