Researchers can be promoted to increase their abilities. This is mandatory for any Comrade hoping to bring true glory to State and crush Capitalism!
Earning multiple of a Researcher will allow you to promote them using Science. The number of each Researcher to collect for next upgrade is shown on the Researcher Card.
When you have enough Science and have collected enough of one Researcher, you will see blue flame on Researcher Card. This indicates you can upgrade the Researcher and is also very cool!
Keep in mind, Comrade, that the higher promotions a Researcher receives, the more Science you'll need to use to promote them further.