There are several reasons that the answer is highly educated may make you liberal, not the college experience per say! The conservative mantra that colleges are nothing more than evil liberal training grounds is a political move. It gives their base someone to hate for their plight, along with immigrants and people of color being the reason for all of the ills in life confronting them!
One of the reasons is, as you get more educated, you are introduced to a wider variety of cultures that you might have been afforded living in a microcosm before college. Your parent’s friends would tend to only be people who mirrored themselves! They would also tend to live in communities that also mirrored their belief system if possible. It is also true that high school students who are liberal tend to also go to college in much greater numbers! Hence a more liberal college population results! It has nothing to do with the college experience itself in that case.
Another possibility might be the growing numbers of women getting college degrees. Women, in general, tend to vote with the Democratic Party more than men. So as the population of highly educated people grew more female, that may have swung it left.
Third, the mainstream population that is conservative tends to be less educated! They do not tend to trend towards the highly educated or attend college, 31 percent of people with post-grad educations are consistently liberal, compared to 5 percent of those with high school educations or less according to the poll I saw! My own research tends to tell me this is factual even if the figures are not exact! Take that as you will, but it was not meant as any kind of detrimental slight! I myself have no college degree. I have gone to college a lot off and on, been to and graduated from several trade schools, let the military educate me to work on computer warfare aircraft in avionics, but basically, I am self-educated. I am liberal in case there was some doubt, but I have no formal college degree!
Yes, rich kids tend to be conservative also, and yes they tend to get educated, but they also tend to stay away from science-related pursuits! They tend to favor education that will help guarantee them a lifetime of successful avenues to get money and to keep it. Ok, not a sin, but you take a look at your GOP Senators, for example. A lot of lawyers, business majors, etc., you find not many scientists among them, no evolutionary biologists, no paleontologists, no teachers, you see where I am going. So you tend to only get a House or Senate with people of one mindset in that party. The other side of the aisle has a tendency to also come from that same background I freely admit that! You will find in the Democratic Party, however, more than a few with degrees in education, or science degrees, way more than you will in the GOP.
Also, if you are religious, especially those influenced by evangelicals, you will, even though highly educated, shy away from any form of study that makes you uncomfortable with what your Bible teaches! So we tend to have a lot of politicians who have absolutely no background in science as it makes them uncomfortable. It also makes them dangerous when it comes to being put in charge of entities whose whole being is based on science. NASA and the EPA are prime examples. You can talk about big government and over-regulation all you want, but big government is what you have right now under the current administration, and getting bigger and narrower in its scope and understanding every day!
These are a few ideas that have come out of this administration. Radiation is good for you, just like sunlight as long as it is moderate! Asbestos, one of our biggest killers, is safe! Dumping into streams and rivers is ok again! The clean air initiative is too extreme, so just get rid of it altogether. Oh, and let’s sue any state that still wants to make clean air a priority! Some GOP states have actually made mentioning climate change illegal; one has stated that you cannot connect rising sea level data to any study of climate change, even though their coastlines are in extreme danger! The white house has actually instructed that anything to do with climate change should just be ignored!
Is this really what you want? Sure the government is full of red tape and it is cumbersome and that does need to be fixed. But these cuts in protections all have one thing in common, a greater profit margin for big business and no concern for health issues. That cannot be the standard!
So, my point is, getting educated in itself tends to make you liberal, it is not that colleges are some kind of evil cabal indoctrinating our youth, they are just thinking for themselves, which has never been good for conservatives. Red states tend to be less educated with a poorer population on average! They also tend to be in need of more welfare than blue states, so why would they want to leave control in their state to the GOP whose leadership is responsible for the condition they find themselves in! Well, in this case, I say they are the ones being indoctrinated, why else would they vote against their own well-being!
I will not go into any moral issues I have with the President and the GOP, as they are more numerous than snowflakes in a blizzard! I just have to believe we will come to our senses at some point!