I meant to say that the left/right divide is built in to humans, not that each individual human is predisposed to always be left or always be right.
The rightward shift as people age is pretty easily explained by self-interest. When you start with almost nothing, you want a fair share because that's more than you have now. Once you climb the ladder, you don't want a fair share because that's less than you have now. Once you get above the average, you want to stretch the pyramid taller because that puts you at a higher absolute position, and the higher up you are, the more you want to stretch it. When you're below the middle, you want to shorten the pyramid because that puts you at a higher absolute position (the pyramid extends below the floor).
But that's assuming wealth dynamics continue to work how they did for boomers. IIRC millennials were the first generation to shift leftwards with age, because they mostly didn't get to above-middle positions on the pyramid.
The rightward shift as people age is pretty easily explained by self-interest. When you start with almost nothing, you want a fair share because that's more than you have now. Once you climb the ladder, you don't want a fair share because that's less than you have now. Once you get above the average, you want to stretch the pyramid taller because that puts you at a higher absolute position, and the higher up you are, the more you want to stretch it. When you're below the middle, you want to shorten the pyramid because that puts you at a higher absolute position (the pyramid extends below the floor).
But that's assuming wealth dynamics continue to work how they did for boomers. IIRC millennials were the first generation to shift leftwards with age, because they mostly didn't get to above-middle positions on the pyramid.
It's the subtle things that keep society stable.