I have a co-worker who I quite enjoy. We are in exactly the same position in a very small company, similar in our love of absurd humor and our enjoyment of clients and getting to explore different technologies and corporate cultures. There is a lot about us that is very similar.
Curiously, our politics are very different. Or maybe not at all curious given he grew up in Georgia a decade before I grew up in California.
We like to think that we choose beliefs but maybe they choose us. And perhaps the vehicle through which they do is the thousands of micro-expressions we're exposed to growing up. Let me explain.
Imagine an earlier time in evolution. You are part of a small tribe and you know that you can't survive on your own. You have an idea for an approach that you think would result in more food. It challenges the old ways though and you also know that it will be risky to push too hard with your idea.
As you propose your idea, you'll be less wed to the idea - which might make things a little better for everyone - than avoiding exile from the tribe - which would make things much worse for you.
So how do you exercise caution when making a proposal that could either make you a hero or an exile? You learn to read expressions, body language, tones ... and you look for early warnings that you might be over-stepping the bounds of convention in ways that will get you kicked out of the group.
To this day, it's probably the case that we learn to read the thousands of clues about "you're in the group," or "you're about to get kicked out of the group" status and we learn to respond to those. That feedback is immediate and important compared to the more abstract feedback about policy tends to make the next generation healthier, wealthier, or wiser.
My co-worker who grew up in Georgia a generation earlier would have been shaped by more conservative feedback than me. It's no surprise that today he is more conservative. And maybe we don't really choose our ideologies so much as learn them as a way to stay within the group we find ourselves in.