Innovators are getting older, working fewer years

Last night, President Obama said American has to "out-innovate" the rest of the world, saying, "The first step in winning the future is encouraging American innovation."

But the economists Tyler Cowen and Benjamin Jones have both painted a troubling picture of the state of innovation in the country.

Cowen, in his new book "The Great Stagnation," points to work that shows that 80 percent of America's economic growth from 1950 to 1993 came from the application of ideas that had been invented or discovered before that time, and heavy investment in research and education. "In other words, we've been riding off the past," he writes.

(The tech entrepreneur and PayPal founder Peter Thiel also theorizes that the pace of technological innovation has been overstated.)

Mike Gibson at A Thousand Nations blog breaks down some fascinating research by Benjamin Jones at Northwestern University that may explain some of this lag: Innovators are getting old. The average age of Nobel laureates and tech innovators when they make their greatest accomplishments has risen six years over the past 100 years. In 2000, the average inventor was 31 when he produced his first invention, in 1900, he was 23.

And it doesn't matter that our life span has also risen, because Jones saw no proportional rise in productivity among 50- and 60-year-olds. The innovation window has narrowed, and Jones estimated a 30 percent decrease in life-time innovation capability over the past century.

(Roy J. Plunkett, the inventor of Teflon, at the National Inventors Hall of Fame in 1986: AP.)