According to a Pew Study, there is polarization in the consumption of news related to political affiliation.
When it comes to getting news about politics and government, liberals and conservatives inhabit different worlds. There is little overlap in the news sources they turn to and trust. And whether discussing politics online or with friends, they are more likely than others to interact with like-minded individuals, according to a new Pew Research Center study.
Other studies See page 27 have found similar results.
The magnitude of the estimate of the taste for like minded news parameter η implies that an ideological distance of one unit between viewer and channel reduces that viewer’s probability of watching by about 2.5%. For reference, at our estimated scaling parameters, the ideological distance between FNC and MSNBC in 2008 is 4.3 units. Given the quadratic-loss specification of ideological tastes, this distance implies that an average demographic voter located at the
ideological position of FNC in 2008 is about 45% more likely to watch FNC than she is to watch MSNBC.
This last study touches on some of the same themes.
Compositional changes in the voting public link cable penetration and the polarization of elections even before the founding of Fox News and the creation of the World Wide Web. Yet, there is little evidence that more partisan messages changed people’s attitudes or behaviors. A key concept, discussed in detail here, is selective exposure. Evidence for partisan selective exposure is mixed and does not, on its own, show media impact.
You also asked about party affiliation generally. The overwhelming indicator for party affiliation, sorry you rebels out there, is mirroring your parents. Although, some interpret their parent's political leanings incorrectly. See Parents See also Teens
“The transmission of political party identification from parents to children remains one of the most studied concepts in political sociology,” political scientists Christopher Ojeda and Peter Hatemi write today in American Sociological Review, yet theories of that transmission have largely stagnated. According to the prevailing view, which dates back to at least the 1950s, you passively adopt your parents’ party affiliation.
As far as Fox regularly crushing MSNBC in the ratings, it has mostly to do with all the major networks, PBS, and CNN compete with MSNBC and Fox has no real network competition. Link