  Although there is mounting empirical evidence for the increase in affective
polarization, few mechanistic models can explain its emergence at the
population level. The question of how such a phenomenon can emerge from
divergent opinions of a population on an ideological issue is still an open
issue. In this paper, we establish that human normativity, that is, individual
expression of normative opinions based on beliefs about the population, can
lead to population-level polarization when ideological institutions distort
beliefs in accordance with their objective of moving expressed opinion to one
extreme. Using a game-theoretic model, we establish that individuals with more
extreme opinions will have more extreme rhetoric and higher misperceptions
about their outgroup members. Our model also shows that when social
recommendation systems mediate institutional signals, we can observe the
formation of different institutional communities, each with its unique
community structure and characteristics. Using the model, we identify practical
strategies platforms can implement, such as reducing exposure to signals from
ideological institutions and a tailored approach to content moderation, both of
which can rectify the affective polarization problem within its purview.
