Very interesting! I've skimmed the paper and what the model seems to refer to is affective polarization (i.e. hatred towards the outgroup).
It gets much more complex when we begin to incorporate other forms (and potentially sources), such as elite, partisan, party and legislative polarization. As umvi mentioned, each of those may be a source or consequence of affective polarization. Or both at the same time!
We really need some long-term field experiments (or natural experiments), but this paper definitely seems like a good contribution regarding the dynamics (models of which often have been way too simple).
It gets much more complex when we begin to incorporate other forms (and potentially sources), such as elite, partisan, party and legislative polarization. As umvi mentioned, each of those may be a source or consequence of affective polarization. Or both at the same time!
We really need some long-term field experiments (or natural experiments), but this paper definitely seems like a good contribution regarding the dynamics (models of which often have been way too simple).