apropos of the below, people actually do want to make the left-right spectrum neurological and genetic. they really do want to make left and right 19th century-style races, literally. and as in 19th century races, people are supposed have different racial/biological natures and destinies, different roles in history. then like the caucasoid race in relation to the negroid and mongoloid races, according to british gentlemen in 1880, the progressive race can assume its destined domination. otherwise we go backwards in history, or even in evolution.
if whether or not you support obamacare is genetic, then we could breed out the right-wingers, or maybe medicate them. so certain are people on either side of the rightness of their own positions, so soaked in empty dogma are they, that neither side would hesitate to fix the other surgically or through starvation-and-reinforcement in order to...whatever, save the earth from warming or keep you from choosing abortion or save the very essence of american freedom, or whatever. this degree of certainty is a feature of beliefs that are taken for social rather than for epistemic reasons; it is entirely out of proportion to any evidence or argument. to have even a normal degree of certainty, or the possibility of backing up should new evidence emerge, would be a betrayal of your people. even to listen to the reasons other people have for believing things would be a betrayal. in this sense left and right are like religious faiths or perhaps i meant to say cults.
that's how committed people are to this completely incoherent bulljive: they really do regard it as a baseline of human existence - so of course it's in the brain - even though the left-right spectrum emerged only in the 19th century. this shows you for one thing the quality of this neurofad and its dangerousness: really it's as good as race theory joined to evolution and phrenology circa 1880. if you listen to people on the left, they keep suggesting that people on the right are at an earlier stage of evolution, like neanderthals or trogoladytes, etc. nature has imprinted on our dna a wretched series of contradictions, as though the people who think 2+2=17 and those who think it's 71 have different neurotransmitters or different cerebral swellings. or it's as though you found that people who like season 2 of scandal have a different forehead slope than those who prefer season 3. jeb bush and hillary clinton don't have different positions on anything, but their brains are different or they wouldn't belong to different political parties.
indeed, from my point of view, the positions amount to the same thing: enthusiasm for the very same hierarchy, slightly differently described (the left loving political hierarchy, the right economic, and these coinciding almost perfectly on the ground). i'd breed that out, if i could.
understand that where you are on the political spectrum correlates with gender, sexual orientation, race, region, income level, age, and so on. so you'd have to make all those things neurologically connected somehow. just spitballing now, but a basically social explanation is actually going to work easily in a million obvious ways, whereas this is just an complete non-starter. it's worth saying, though, that neither the neurological nor the social explanation is relevant to the truth of the positions, so if either works overall, no one believes any of these things because they have reasons to think they're true. well, that much is obvious anyway.