After a man has children, the odds are significantly lower that he'll contribute some world-changing discovery. This is not because his ability level has decreased - Marc's article suggests that quality of work remains constant. Rather, it's because he has no reason to. He's already reproduced, and likely found a lifetime mate. His children's genetic legacy is set in stone. There's no reason for him to expend the extra energy needed to perform at the top of his game.

Curiously, men that continue to produce at top-of-the-field levels also seem to have multiple successive wives/lovers. Look at Rudy Giuliani, Richard Feynman, Albert Einstein, Benjamin Graham, etc. Perhaps they remain geniuses because they see the reproductive game as not over yet, and hope to continue to impress younger, more beautiful women.

Only one thing on that list actually works, and that's why so many guys are in bands... and why the Rolling Stones are still touring.

In physics, this usually turns out to be people younger than 26, often through seminal PhD theses. But not always. Sometimes people dabble in secondary fields at older ages and come up with significant breakthroughs, like Linus Pauling (http://en.wikipedia.org/wiki/Linus_Pauling).

I'm not sure what I think about this regarding entrepreneurship. It seems that very successful entrepreneurs are not always coming up with revolutionary thinking, but instead executing well and paying attention to small details that make things work where they haven't before. As such, the age indoctrination barrier may not be as present as it is in physics. But of course there are the risk and drive barriers--people get settled and less willing to take risks and go through the arduous process of starting something new later in life.

The reason for age was simple - as you grow up there are more dependencies which demand a share of your time and more responsibilities to live up to - which is what pulls you down. The age question was not about productivity. Given equal circumstances and responsibilities, there is no question that this thesis would hold true - however that is not the case !!

Sorry Marc - this time it was thought through a little tooooo much and the original reasons that started this debate were largely ignored. I hope you read this comment.

Something like...say...Twitter. What 50-year-old would even consider doing something like that? And if a kid does it, and botches it, no one gets hurt. Clearly the trade-offs between enthusiasm and experience are at work.

Dr. Simonton points out that the periods of Beethoven's career that had the most hits also had the most misses

I can't find that in the article. If by "hits" he means contemporary hits, perhaps. But Beethoven's late stage was both sparse, and choked with his greatest works. Compare that to rock music...the rolling stones' past 30 years can't compare with any 3 consecutive months in the 1960s.

Have you heard about the Boeing 787 (http://news.bbc.co.uk/2/hi/business/6282820.stm)?

Have you heard about the concorde? http://en.wikipedia.org/wiki/Concorde (maiden flight: 1969, when the Rolling Stones were peaking.)

Is it? It's an all-new design, using a new material for the first time, etc.

I didn't mean to be so blunt in my first reply, but there are tons of improvements that can be made in that industry, especially if you look at old problems with new eyes.

If you want to talk about all new designs and brilliance in aerospace, look at Burt Rutan.

And the point is: if a generalization about an industry is incorrect, it's not a good idea to use that as a logical foundation for predicting the age of entrepreneurs in that industry.

If it isn't the plane itself, it's the business model (westjet/southwest?). The problem with the industry - like others such as insurance, banking etc. - is the huge startup costs.

When you have larger start-up barriers, you get less incentive to innovate. If you're being bankrolled, you'll innovate, which is why the USAF had a new fighter every ten years when the cold war was on.

Of all the conclusions, this one threw me off quite a bit. I realize Marc is going to be following this article up with a part 2, but I d be interested to see just how a "swing at the bat" is defined in the start-up context. If a swing is defined as one iteration, then seeing no "systematic developmental trends" in the "quality ratio" goes very much against the grain. I would argue that every iteration teaches us something that is quite applicable in the "general" sense to future iterations (for different products/services and across markets).

In any case, even if this conclusion is considered in a non-startup context, its still very bothersome. For example, if a "swing at the bat" is defined as one complete work, such as a Book or a Musical Piece, why arent there developmental trends in the quality ratio?

I'm thinking in terms of authors vs. physicists: you absolutely cannot write a novel until you have the life experience needed to write a story that resonates with readers. However, performing an experiment that resonates with other physicists isn't a paradigm shift; it's normal science. Valuable, but not world-changing.

It seems like it applies to many other fields though. CEOs peak in their 60s; their job consists of internalizing the culture of their organization and making wise decisions based on that experience. Lawyers peak in their 40s and 50s; their job consists of internalizing court precedents so they can predict how a judge or jury will rule. Musicians peak in their late 20s and early 30s; their job consists of internalizing the conventions of existing musical forms and turning that into something new and fresh. Entrepreneurs peak in their 20s; their job consists of recognizing ideas that others have overlooked and convincing the world that those are good ideas.