As I’ve reported before (and here) when it comes to political affiliation people don’t behave rationally. Our son James also has expressed frustration at this irrational behavior. Here is some research (via Lyle at UltiMAK) that attempts to explain why people do it:

“These sacred truths are unverifiable, and unfalsifiable, but the faithful nevertheless accept them to be unquestionable. In doing so, like assemblies of the faithful since the dawn of language, they bind themselves together for protection or common action against unbelievers and their lies.”
–Nicholas Wade, Before the Dawn, p. 165-166

When people in business meet for the first time to discuss a transaction, they often exchange what I call “trust cues” in order to reduce mutual suspicion. For example, they may recite empty phrases from popular business books, such as “win-win,” “synergy,” “principles,” “customer-driven,” or “raising the bar.”

Nicholas Wade provides a readable, wide-ranging survey of the impact of recent advances in genetics on anthropology. In one chapter, he argues that the origins of what I observe in business behavior can be found in early religious rituals. Religions produce trust cues. Trust cues are necessary for large societies and trade among strangers to emerge. They serve to protect people from cheaters and liars.

What I am going to suggest in this essay is that political beliefs can serve the function of trust cues. Political beliefs may have at best a tenuous empirical basis, but they function to demonstrate one’s membership in a trusted group.

I am impressed. That helps me understand better.