<p>Concerns over ideological polarization are increasing, and ideological citizens’ pro-attitudinal media exposure has been suspected to worsen polarization in modern democracies. However, the psychological mechanism mediating pro-attitudinal media exposure and political polarization remains uninvestigated. This study modifies and extends the influence of the presumed influence model to investigate media influence in ideologically polarized politics. Specifically, the proposed modified model (1) categorizes the target group of others in presumed media influence into two –– the ideological ingroup and outgroup; (2) conceptualizes presumed media affect (i.e., perceptions of others’ like/dislike of the media); (3) includes perceptions of others’ attitudes on an issue; and (4) tests the effect of pro-attitudinal media exposure on ideological citizens’ own attitude extremity and potential mediation by other factors. The results of an online experiment show that pro-attitudinal media exposure drives more extreme attitudes in ideological citizens by strengthening their perceptions that others dislike the media or that the media influence others.</p>