I find it fairly plausible that liberals are more open to new experiences, while conservatives are more conscientious and have a greater need for cognitive closure (ie, certainty). If you look at liberalism and conservatism purely in terms of species instinct, they form a balanced yin-yang of survival values. Too much conservatism and you stay in your safe little cave and starve to death. Too much liberalism and you get eaten by a tiger.
A lot of traditional conservative/liberal dichotomies can be seen in this way. Environmental protections tend liberal, because they are about acknowledging the inherent limitations of the cave (choking on your own waste is one of many ways the safe little cave becomes a hideous death trap). Military hawkishness tends conservative, because !!!TIGERS!!!
Now, I think that most people as individuals are a swirling dynamic mixture of liberal and conservative impulses. We’re certain about some things and not others, cautious in some areas and not others, afraid of tigers in some areas and not others. Some tigers will terrify us, while others will merely inspire a feeling of mild apprehension. And, when it comes to those areas, our level of comfort changes over time.
Some people tend very liberal, or have a strong personal stake in the matter at hand, and will therefore be the first ones out of the cave. Others — maybe most — will hang back a bit, and wait for that first group to get eaten by tigers or not. And when they don’t, the rest of the group will start to venture out there too. Gay rights is a perfect illustration of this, as what was once an extremely liberal position (pro same-sex marriage) has become a moderate mainstream position.
Sometimes, after this has happened to them often enough, people will actually start thinking of themselves as liberals — when they realize that it has never really been the right choice to stay in the cave, and the tigers never turned out to be as fierce or numerous as they were made out to be.
At this point in history, though, the political right has been radicalized to the point where it no longer seems accurate to call them conservative. Not only are they extra-resistant to change in certain predictable areas, but they passionately advocate for undoing changes that have already occurred.
It’s as if, venturing out of the cave and finding it quite nice and remarkably tiger-free, they were nevertheless hit with a crippling attack of agoraphobia and went rushing back into the stinking embrace of the cave.
Now they are deep in denial, pretending that the cave is perfect, of course, and will always be perfect, and a veritable army of tigers prowls outside, ready to swallow us all. Worse, in order to foster the illusion that they must stay in the cave, they can’t let the rest of us leave either.