Isaac Newton was just 23 years old when, while on a brief hiatus from Cambridge University, he developed his theory of gravitation. “For in those days I was in my prime of age for invention, and minded mathematics and philosophy more than at any time since,” he later wrote in a letter to a fellow scholar.
Similarly, at age 26, Einstein published the paper on the photoelectric effect that would win him a Nobel Prize 16 years later in 1921. Marie Curie was around 30 when she, along with her husband Pierre, discovered the radioactive elements radium and polonium.
But according to economists Benjamin Jones and Bruce Weinberg, young scientists making groundbreaking contributions to their fields are becoming an endangered breed. In a study published yesterday (November 7) in the Proceedings of the National Academy of Sciences, they reported that the chances...
Their analysis of 525 Nobel Prize winners (182 in physics, 153 in chemistry, and 190 in medicine) between 1900 and 2008, revealed that while the mean age at which they did their Nobel-prize winning work was around 37 for the three fields in the early 20th century, they are now around 50, 46, and 45 for Physics, Chemistry, and Medicine, respectively. The Scientist spoke to Weinberg, a microeconomist at Ohio State University, and Jones, a macroeconomist at the The Kellogg School of Management, Northwestern University, about the trends in age and creativity in science, and what they may mean for the future of science research.
The Scientist: As economists, why are you interested in when scientists are making their biggest contributions to their fields?
Benjamin Jones: In an advanced economy like the United States, technological and scientific progress is a primary driver of economic growth and prosperity. Therefore, studying how innovation happens is critical to understanding economic outcomes. One of the puzzles that has been in my mind and in a lot of other economists’ minds for some time is that we put more and more effort into research and development—more people, more dollars—but the growth rate of the US economy remains fairly consistent over time; it doesn’t rise despite the fact we try harder and harder. The implication of that is that the contributions of individual researchers to the overall economy seem to be declining with time.
Bruce Weinberg: What we find is that there are substantial shifts over time within the fields in terms of both the prevalence of theoretical contributions and the amount of knowledge and the amount of time that it takes to get to the research frontier in fields. Those relationships then map on to and are reflected in the ages in which people are doing their more important work. As the amount of knowledge in a field accumulates—[for] which we have one direct measure based on backward citations in articles, and one indirect measure based on when people receive their highest degrees—the great contributions come at later ages.
TS: What pattern did you observe concerning age and creativity in science throughout the 20th century?
BW: In chemistry there’s a shift to older ages over the course of the 20th century. In medicine you see a decline in the frequency of very early contributions. So people aren’t really making Nobel contributions before age 30 in medicine anymore, whereas they did earlier in the 20th century.
BJ: But what’s really interesting is that in physics, during the early 20th century it’s going the other way very strongly. Suddenly there’s a big burst of work by young people in the 1920s and 1930s, and this is associated with the quantum mechanics revolution, which was a time when people realized, because of a small number of empirical irregularities, that classical physics didn’t seem to be explaining what was going on at a very micro level. So it was kind of open season. But as quantum mechanics becomes more established as a very powerful and effective theory for explaining empirical facts, you start to see…a shift toward experimental work again, and that’s associated with older scholars relative to younger scholars making great contributions. Interestingly we, we don’t see the same type of dynamics [for chemistry and medicine]. We see a smoother decline in very young scholarship, for example, which suggests a smoother increase in foundational knowledge and with that perhaps a smoother shift toward more experimental work.
TS: Some studies suggest that creativity declines with age and may peak before middle age. How does that finding fit with this trend?
BW: There are different ways of making important contributions. One is more abstract and theoretical and the other is more empirical and experimental, which is based more on the accumulation of knowledge. It is the case that the theorists on average do their best work earlier in their careers than the empiricists and experimenters. The people who are making these important contributions later in their lives are really making those contributions using a different approach than the people who are making radical early career contributions.
BJ: If people are naturally very productive in their 20s, either because there is some innate physiological advantage or because they are just very energetic and have strong incentive, but instead they’re saddled with having to learn all this accumulated knowledge, that does suggest that we are taking a chunk out of people’s innovative capabilities at a time in their lives when those capabilities are potentially very high. That suggests there’s a really strong opportunity cost. That doesn’t mean that’s an easy problem to solve because it is necessary for these scholars to become experts before they can really make a big contribution. It’s also the case that there’s more to know and you just can’t know everything. One implication is that people become much narrower experts. That also makes people’s creativity a bit narrower.
BW: In a more policy context, there is extreme angst at, for instance, the National Institutes of Health, over the fact that they’re funding an increasingly aging pool of researchers. That’s something that has caused a lot of concern. There are a variety of reasons why you would want more support going to young investigators. The young investigators may simply drift away from science to industry or to other endeavors if they simply can’t get funding earlier in their careers. But in so far as we’re finding that… at least in some of these fields, people are increasingly making important contributions later in their lives, it does suggest that some of the concern may be overstated.
TS: What do these trends mean for the future of science?
BJ: We do see that contributions per researcher to the overall economy seems to be declining with time. If these trends continue, it is alarming, because [researchers] are less productive overall. The way we go about that traditionally is we throw more and more people at the problem. So it’s okay in a sense if there are less contributions per person if you can throw more minds at it. One of the interesting questions is, as these trends continue, can we keep throwing more and more resources, people, and dollars of the society at this problem? If we ultimately can’t do that then we need to think of other ways to make the research process more efficient.
B.F. Jones and B.A. Weinberg, “Age dynamics in scientific creativity,” PNAS, doi: 10.1073/pnas.1102895108, 2011.