There are several distinct ways that optical illusions work. Most of those methods involve the brain taking shortcuts. It makes assumptions based on observations from the nearby area and the past. It knows what a smile looks like, it knows what movement looks like. When it sees something similar, it assumes a smile or movement are occurring. It knows that a half sized human riding a half sized horse is most likely farther away, not actually half sized. You don't just see a color, you see it in relationship to the colors next to it.
(Great source for optical illusions.)
Your brain does the same thing with politics. You look for things and clues you recognize and assume they exist in other places. If you live in a place where the only minorities exist in TV shows, usually committing crimes, that's the first thing you think of when you see a minority do. If you live in a world where the cops never show up in time to stop a crime, but routinely stop and frisk you for no reason (often very rudely), then you don't trust cops.
If you were given opportunities and became wealthy, while you saw others fail to take advantage of those same opportunities, then you think anyone can be wealthy. If they aren't, you ask yourself what's wrong with them, as opposed to admitting that they might not have been given the same opportunities.
But lets take a look at what those surroundings are, comparing liberals with conservatives.
American conservatives tend to be: (source)
- Rural rather than urban
- Protestant as opposed to Jewish AND observant as opposed to less religious
- White (particularly in the south)
- Extremely wealth as opposed to extremely poor
- Not in a Labor Union
- Less well educated
- Owns guns
The stereotypical liberal is a poor, black/hispanic/asian, lesbian, Jewish woman that does not keep kosher. She is single, belongs to the AFL-CIO, lives and works in a city, has a Masters in English Literature and has only seen guns in the hands of a cop or a criminal.
Let's see how those things affects both of their view point.
1) Living in a rural area means you don't think local government does much. The bus don't run very often, it take 20-30 minutes (or more) for a fire truck, ambulance, or cop car to show up, and you have to maintain a septic tank because the town doesn't have a sewer system. Rural areas don't have a 311 system. But on the other hand, if you live in a city, you get a LOT more services. Also, those service you do have work a lot better because it is easier to do them in even a small city. If you live in a city, then government works a lot better. You might even say it works well. If you live outside of a city, it just doesn't work anywhere near as well. Also, the smaller a government agency, the more likely it is to be corrupt from head to toe. It's easy for one corrupt sheriff to get elected and abuse his authority - he could be the only competent cop in the entire county. It's harder when there twenty other competent and honest police men - plus an FBI office down the street, and an internal affairs office in the same building. Sure, there are just as many corrupt cops in the city, but they get watched and checked up on a lot more than a county sheriff.
2) Being Protestant, no one ever really discriminated against you based on religion. When some rude person starts yelling about how Jesus will save you, you agree with him on principle even if you wish he would be quiet. You never had someone think you must be evil because of your religion. No one ever mistook your for an Islamic terrorist even though you are a Jew or a Hindu that has been fighting Moslems for the past 100 years. People don't think of you as a cult, they don't demonstrate against your church being built, they don't treat you like you are evil simply because you are being faithful to the peaceful traditions handed down by your parents. In addition, as you are observant, if your friends and family fail you, you can turn to your church and ask them for help.
3) Similarly, you never experienced real prejudiced based on the color of your skin. No cop ever stopped you for a stop and frisk, no one ever turned you down for a job because of your accent, no one etc. etc.
4) Being male, you never had someone try to tell you you have to have that baby, you can't get an abortion. You get paid more than women do, you don't get sexually harassed, etc.
5) Being married, you have a better support system of friends and relatives. You have double the number of relatives and you can depend on your spouse's friends as well as your own.
6) You live a childhood without real worry. Your parents sent you to college, as opposed to not going or taking out loans. You never depended on welfare when you got fired after your boss ran the company into the ground (or worse, embezzled from your pension plan).
7) You never had to strike to get a raise. You never had to unite with your fellow workers to get a good bargaining position. You never had to suffer bad working conditions because your Union failed to win a negotiation.
8) You never experienced anti-gay discrimination. Your spouse has insurance, rights to your kids, medical rights, inheritance rights, citizenship rights, etc.
9) The highest status and greatest authority you personally knew (before starting to work) were clergy. You probably never met a very intelligent college professor who exposed you to the idea that you could be knowledgeable without being religious. Your church did many of charity activities that the government could afford to do in a major city - such as give shelter to the homeless.
10) You know a lot of people that own guns and use them responsibly. Chances are, none of them are criminals, and you've never seen a gun in the hands of a criminal. You probably have cherished memories of using your gun with your father and/or friends.
Not everything here will shape your beliefs, but it is not that surprising that the political party composed of people that have never experienced real prejudice, never seen effective government, never needed government aid, and whose most respected elders are clergy, and who have a lot of good experiences with guns:
Doesn't understand prejudice, doesn't think government works, doesn't think we need government aid (because they get more aid from non-government sources) and gives excess respect to religion, not enough to scientists, and don't see a problem with gun ownership.
Similarly a party composed of people that has been discriminated against, hasn't seen guns except in the hands of cops or criminals, doesn't have the same family support structure, mostly poor, that has had employers ignore their needs to the point they need to strike (no one wins in a strike), and has seen the value of education believes:
They need protection against discrimination, guns are dangerous, they need some government support in bad times, and respects scientists.
I'm not saying that either viewpoint is correct (well, not today - most other days I'll claim liberals are right) but I am saying that is why people have these viewpoints.
Your viewpoints are shaped not just by the facts, but your life experience.
But those viewpoints do not reflect reality, they reflect just a limited, prejudiced point of view. You are always missing something because your mind simply can not understand something without a lot of context.
When you judge other people, you should account for this. They are not trying to get rid of the gun you have fond memories of using with your father, they are trying to get rid of the gun they saw in a muggers hand last week. They are not trying to eliminate healthcare for your government job, they are trying to have you buy it privately so that that no one got kickbacks for arranging for it.
A smart man recognizes these different points of view, instead of demonizing people for having them. This lets you forge a reasonable compromise.