idk. i don't know anything about brains. just some pop science articles i've read.
i think its a matter of degrees too, they're not saying tories have no empathy, maybe just harder for them to reach a place where they feel it... the other things i remember were a stronger impulse to feeling disgust & less capacity for uncertainty/understanding conflicting information.
read a book called tribes by sebastian junger recently which had some stuff about this - like how the two political/personality archetypes go back through human history and were essential components to having a successful tribal society, where the everyone-for-themselves concept was useful & ascendant in times of plenty in order to expand, but in times of hardship tribes would self-regulate back to a sharing model. & how this doesn't really work in the society we have today where expansion is unnecessary.
i know a lot of people (on the left especially) don't like biological/evolutionary psychology stuff and it doesn't make for a very hopeful reading of humanity. i don't know how much i buy into it either tbf, but... yeah.