I’ve been reading much about tribalism as it pertains to what’s been going on in the United States recently, and found this piece very illuminating—especially since I sometimes see Us vs. Them dynamics emerge in Dhamma circles.
The (in)famous Robert Wright has also written about how mindfulness can help deconstruct the cognitive and affective biases that fuel in-group/out-group contempt.
It is called the Mana (self identification) one of the ten fetters in our make up including animal and Deva etc. It is one of the latent factors (Anusaya) as well.
If you read the book entitled “The Rational Animal” which is all about modularity of mind (Rob Wright is big into the modular view of the mind) it goes deep into these intrinsic biases. The “tribalness” of people is discussed in the book, and they share some great insight indeed.