“Age and Great Invention”

This is from Benjamin Jones:

Great achievements in knowledge are produced by older innovators today than they were a century ago. Using data on Nobel Prize winners and great inventors, I find that the mean age at which noted innovations are produced has increased by 6 years over the 20th Century. I estimate shifts in life-cycle productivity and show that innovators have become especially unproductive at younger ages. Meanwhile, the later start to the career is not compensated for by increasing productivity beyond early middle age. I further show that the early life-cycle dynamics are closely related to variation in the age at Ph.D. and discuss a theory where accumulations of knowledge across generations lead innovators to seek more education over time. More generally, the results show that individual innnovators are productive over a narrowing span of their life-cycle, a trend that reduces, other things equal, the aggregate output of innovators. This drop in productivity is particularly acute if innovators’ raw ability is greatest when young.

Hat tip goes to Mike Gibson, read his post.

Here is a Gideon Rachmann column from today, on a similar but not exactly the same question.  I agree with his penultimate remark on the division of labor.

Comments

You learn less science at school than you could, because your classes are cluttered with duds; possibly true at University too. You spend longer doing your degrees. You then do postdoc jobs, plural - you are not treated as an independent scientist until you're well into your thirties. And you are selected for as someone prepared to run in this boreathon.

The man to read on this is Bruce Charlton.
http://medicalhypotheses.blogspot.com/2009/02/why...

> Yeah, but is there any evidence there was less of this fluff in the past?

And the guys who become top achievers are probably not much distracted by the fluff.

"In 1900, global average lifespan was just 31 years, and below 50 years in even the richest countries" -
http://www.who.int/global_health_histories/semina...

Though the 'young people are more innovative' thing is likely important, people now have more than 6 more years available to them to work with their problems simply because they can expect to live a lot longer than early 20th century scientists could.

"you are not treated as an independent scientist until you're well into your thirties."

Correction:

"you are not ACKNOWLEDGED as an independent scientist until you're well into your thirties."

Proxy confirmation of Schumpeter's claim that innovation would become less the product of individuals and more of "teams of trained individuals"? In other words, we become more adept at finding and maintaining successful groups as we become older?

If you are spending all your productive years in college learning a bunch of stuff that has little to do with creating new things, then you are going to have this kind of narrowing. Of course, if people actually learned anything at all in elementary through high school, college wouldn't be as necessary -- and if college taught you anything, graduate school wouldn't be as necessary.

"innovators have become especially unproductive at younger ages"

Check out Lee Smolin's "The Trouble with Physics". I don't pretend to have the familiarity he does with the subject, but he notes that in physics, as in many areas, younger thinkers have a difficult time pursuing their own ideas because they instead have to focus on ideas favored by older colleagues, e.g. to pursue tenure.

@gwern

I know child mortality was much higher back then and that people getting a Nobel by definition weren't among the people who died before they started going to college. But people in the US still on average live 25 years more now than they did at the beginning of the 20th century and far from all of that comes from lowered mortality in the, say, 0-15 age range. A perfectly healthy 25 year old could die from pneumonia a 100 years ago, if he was unlucky. A type one diabetic diagnosed at any age would be dead back then, today he or she can live on for decades. If scientists were more likely to die before they got old back then, the breakthroughs that did happen all else equal were more likely to be made by young people.

I never said it was the whole story, but I fail to see how it isn't part of it. I also considered including a remark similar to Rahul's remark above as well, the low-hanging fruit thing is important too.

"Proxy confirmation of Schumpeter's claim that innovation would become less the product of individuals and more of "teams of trained individuals"? In other words, we become more adept at finding and maintaining successful groups as we become older?"

This was my thinking, granted better articulated.

"What sort of evidence could test the low-hanging fruit idea?"

I'd assume some sort of market cap studies would be useful. More generally, I guess one could look at productivity numbers. I do know that Tyler's shameless self promotion has me intrigued, and I'm probably going to have to buy the book on my Kindle (not a truly new innovation to be sure, but a handy one no doubt) now.

Interesting comments re science.

My $0.02: first, (although the plural of anecdote is not data), when I read about scientists 100 and more years ago, quite a few of them died before 50. TBC was an especially prolific killer in cramped European cities.

Second, the amount of knowledge has increased massively in the last 100 years. Current mathematics major student will study, well before graduation, things that were the cutting edge of scientific research in 1900.

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