Before it meant a policy institute, think tank was slang for your skull
From the 1890s until the 1950s, Americans used think tank to mean the braincase, often to mock someone's poor judgment. Only later did the phrase attach to organisations like the RAND Corporation, and by the 1980s and 1990s it meant any independent policy research institute. Today there are thousands of them worldwide.
Around 1958 the Center for Advanced Study in the Behavioral Sciences became the first body regularly called the Think Tank in print, though it does not regard itself as one in today's sense. In the 1960s the label stretched to expert meetings, electronic computers and independent military planners, whose prototype was RAND, spun off from Douglas Aircraft in 1946 and independent from 1948. During the Second World War such bodies had been nicknamed brain boxes.
The historian Jacob Soll traces the idea much further back, to the 800s, when European rulers hired teams of independent lawyers to argue their tax and political rights against the Catholic Church, a practice running from Charlemagne to 17th-century France. He cites the Académie des frères Dupuy, set up in Paris around 1620, and the Club de l'Entresol, active from 1723 to 1731, as early examples.
Modern think tanks took shape in Britain across the 1800s and the opening decades of the 1900s; the Royal United Services Institute dates from 1831 and the Fabian Society from 1884. America's oldest, the Carnegie Endowment for International Peace, was founded in 1910 with a mandate to hasten the end of war, and the Brookings Institution followed in 1916. The Cold War spurred many more Western institutes, and after 1991 the growth moved to non-Western regions, with foreign backing especially visible in Africa, Central Asia and the former Eastern bloc.
More than half of today's think tanks were founded after 1980. Estimates of their number vary widely, from over 11,000 in 2014 to about 6,500 in October 2025. They range from scholarly research outfits to openly ideological campaigners, and output differs hugely: the median publishes 138 articles a year, while Brookings produced 3,880 reports in 2020 alone.
Source: Think tank
