Why science is becoming less innovative

A huge study suggests ageing scientists are part of the problem

AN INFLUENTIAL STUDY in 2023 found that science was becoming less transformative, producing fewer breakthroughs and more incremental advances. A new paper suggests a reason why. Analysing the careers of 12.5m scientists, Haochuan Cui and Yiling Lin, both of the University of Pittsburgh, along with co-authors, find that scientists become less likely to produce disruptive work as they age. Younger researchers are more likely to overturn established ideas or open entirely new lines of inquiry. Older ones still produce novel work, but increasingly build on existing theories rather than challenge them. That may give younger countries an edge over older ones.

Analysing the careers of 12.5m scientists, Haochuan Cui and Yiling Lin, both of the University of Pittsburgh, along with co-authors, find that scientists become less likely to produce disruptive work as they age. (PEXEL)

Chart 1

The study tracked scientists who published papers between 1960 and 2020. It found a clear shift over the course of their careers. Part of the reason may be nostalgia. Scientists, like most workers, become attached to the ideas that shaped them. The paper each researcher cited most often was usually one published near the start of their career. Thus as their careers advanced, the average age of the papers they referenced also rose.

Chart 2

That pattern became especially clear in America after it ended mandatory retirement for academics at the age of 70 in 1994. The average age of papers cited by American scholars increased relative to those cited by their British peers, who were forced into retirement at 65 until 2011.

Chart 3

As well as referencing older material, senior scientists may also be inclined to defend established ideas. The study found that older researchers were more likely to criticise newer papers, often referencing older work as evidence. At the same time, they were less likely to have their own work explicitly criticised by other researchers.

That has consequences for scientific progress. In countries with older workforces, such as America and Japan, disruptive papers account for a smaller share of research output than in younger countries, such as China and India. And in an age of great-power rivalry, that matters.