Why is it that the left seems to form their intellectual tribes in academia and the right seems to form them in think tanks?
I don't see the two as comparable. The main purpose of academia is to educate paying students, the main purpose of think tanks is to influence policy. There are both left and right leaning think tanks, that there are more of any type of think tank is more indicative of where psuedo-lobbying money is coming from than anything else.
In other words, academia may be more left leaning, and think-tanks may be more right-leaning, but these are for very different reasons and aren't necessarily comparable. Think-tanks are going to represent whoever is willing to spend money on think-tanks, academia is not so straight-forward. Asking why academia is generally more left-leaning would be a good question, just find a source that backs up the claim that academics in the fields relevant to think tanks (economics, polisci, etc. as I'm sure the arts are more skewed) are more left-leaning.
The US right tends to be more religious than in many other Western countries, in line with the US society being so.
On the right, white Christians dominate, with whites from "evangelical" denominations making up the plurality of Republicans and Republican leaners.
And only 11% of evangelicals think humans evolved due to natural processes; and even if you add God into the mix as some kind of God-guided evolution that only rises the percentage to 38% of evangelicals who belive humans have evolved at all.
Basically the US right is more "anti-science", not in a general sense, but the religious right surely is on some issues, and some harder-to-circumscribe part of right (probably freedom/lifestyle oriented) on others like global warmming.
Among the nations we surveyed, the U.S. has the highest carbon emissions per capita, but it is among the least concerned about climate change and its potential impact.
That poses a "bias" problem for some scientists/academics from the get-go. If you think the theory of evolution is correct, you're already left-leaning in the US. Likewise for global warming, which doesn't have a religious basis for distrusting it (that I know of), but nevertheless is a feature of the US right.
I'm not saying these are the only issues that matter, but it's hard to work in academia while holding views far outside the academic mainstream.
The premise does not exclude left-leaning think tanks, rather it suggests that the "intellectual tribes" on the left are primarily somewhere else. However it is still worth looking at the think-tanks that are actually out there.
Here is a list of think-tanks in the UK. From the descriptions given they appear to cover the political spectrum reasonably well.
Likewise, here is a list of think-tanks in the US. While there seems to be a disproportionate number in the "Libertarian" category there are also a number that are "Liberal" or "Progressive".
I'm not sure about the right and think tanks since it is not mutually exclusive. There are many liberal think tanks. By the same token not all universities and colleges are liberal but a majority do expose the progressive liberal agenda.
It is not difficult to see why liberalism has found a home in colleges and university. The ideals of liberalism: fairness, equality and universal acceptance, civil rights. These ideals boil down to social change which is easier to attach to if you are the audience of the university and most likely young, have no career and have few responsibilities.
The answer is self selection. If the audience of the university expects liberalism, they will select liberal professors, so the university will hire liberal professors to fit the demand
The reason I chose liberalism as a stand in for the left is because the questions appears to be asking about ideology, not the political spectrum. In most discussions of the recent few decades, the left and liberalism are synonymous.
The argument for the summary of the liberal ideology is social change is in the agenda itself. For example, what social change would be needed if everything was already fair, civil rights were universal, everyone was already equal.
There is a tendency to the progressive ideology when one is young and can participate in all the things that can incite social change. Later in life it becomes more difficult with the pressures of life lowering one idealism. It is a tendency, not an absolute. Can you as a 20 year old get on a bus, stand in line, and walk all day in a demonstration. Can you do the same thing at 35 where you will need a baby sitter, save up money and not have the aches and pains of standing in cement?
I'll come at this a little differently. Environment.
I'd argue, that going to University tends to make people more liberal because the environment tends to be more liberal. Going to University has a whole host of benefits.
Quoting the Ivy League here:
A college education is the most effective way I know of transcending the distinctions—whether of ancestry, wealth, or race—that fragment our society.
This is an important idea because what it means, is that University is about change. About changing to accommodate the economy and society. The most demanding jobs, typically require college.
So why all this set-up? Because when a young adult leaves home, they're typically surrounded by diverse, politically active people. They debate, they exchange ideas, they observe. Also, because of the transformative nature of education, it's a "change heavy" experience that tends to be a net positive for many individuals.
This is not to say that Conservatives aren't educated, they are. However, Conservatism is a bit of a tent. We have both fiscal and cultural conservatives and they tend to have different ideas about how things should be organized.
One somewhat controversial point I'll make, is the conflict between religion and science and I feel this could alienate conservative students. So it might force them to be more insular while at university.
There's also the broader social movements which tend to stem from universities around social justice. The reality is the next generation often wants to rebel against the previous. This leads young people to activism. This also creates friction because Left leaning movements tend to want change. Right leaning movements value tradition.
I want to be clear, I'm not saying being Conservative is regressive or that being Liberal is progressive. I'm saying:
The university experience is distinct in that it has two key features: It focuses on change and you're surrounded by a lot of different people and these conditions likely inform people's politics, because experiences define politics to some degree. That's why Academia is left leaning. Because it sort of self feeding: You go to a university, then you decide to move up in academic rank, which then you must network with other academics and the environment sort of insulates itself from the outside.
Why are think tanks Right leaning? Money. Simple as that. They're academics too, except they get paid by the private sector and there's no education involved. These organizations tend to be fiscally conservative too, but not always. They can be non-profit but it's in essence academia that is focused on preserving tradition and sensible fiscal policy.
To be clear, one isn't better than the other. All policies should be evaluated on their own merit.
Science as a rule cannot remain still. It is constantly progressing forward as old theories are discarded for better theories, and our understanding of the world grows. 'Publish or perish' as the old yarn goes. But it doesn't care about you as an individual. Well, not much. Unless somebody else can do what you did, it isn't science. As such, scientists have created communities that balanced competition and collaboration since a few hundred BC.
The idea of think tanks is believed to have originated around the time of Charlemagne, as while the Catholic Church had a good deal of smart people who didn't have to work for a living to write justifications for their heavy taxation, several monarchs didn't have the educated and 'liquid' human capital to properly argue against these taxes. So monarchies began hiring groups of educated men (lawyers) to properly refute the Church's claims and represent the monarch's legal interests.
So while both entities have a strong history of collaboration towards common goals, science has its roots in progress without regard for consequences, and think tanks have their roots in preventing consequences without regard for progress. These biases inform how we look at each type of group.