The seven-layer
burrito tribal breakdown makes sense if you figure that, often, groups two steps away from each other find it difficult to talk to each other, and are willing to do battle.
The edges are highly engaged and doing fierce battle with each other. 2, 3, 4 and 5 are called the "exhausted majority" by the study. What's interesting is that, from one perspective, the edges often have more in common with each other than with the middle. On political things, but also on some cultural matters:
This gives them a weird commonality that the middle doesn't share. I find that, as a politically disengaged 4, people in 1 and 7 are both often apoplectic over my opinions. ("What do you mean, you can't say for sure on Kavanaugh!")