Does your vote depend on which news channel you watch? If you are a regular viewer of Fox News, will you become more likely to vote Republican?
Until recently, it has been impossible to answer that question empirically. Sure, Republicans tend to favor Fox News and Democrats tend to prefer MSNBC. But if Fox viewers are more likely to vote Republican, it might well be because of the conservative views that led them to Fox in the first place.
An ingenious new study, by Gregory J. Martin and Ali Yurukoglu of Stanford University, explores whether people’s voting behavior really is influenced by what they see on cable news. Their research starts with the fact that, in different parts of the United States, the stations found on specific channels vary. It turns out that, when it comes to the total number of viewers, channel location matters a lot. People are more likely to watch stations in the lower positions. For historical reasons, Fox News and MSNBC have sometimes received advantageous channel positions – but sometimes have not.
So Martin and Yurukoglu explored, across recent time periods and in various parts of the country, the relationships among channel positions, people’s intended votes, county-level presidential vote shares, and individual viewership. With several large data sets, they tested the effects on voting of watching Fox News and MSNBC.
One of their preliminary findings is that Fox and MSNBC have both grown more ideologically defined, and Republicans and Democrats alike are aware of that. In 2000 and 2004, a typical Democrat was no more likely than a typical Republican to watch MSNBC. By 2008, a typical Democrat was 20 percentage points more likely to watch MSNBC. In 2004, a Republican was only 11 points more likely than a Democrat to watch Fox. By 2008, the gap widened to more than 30 points.
The authors also found that both Fox and MSNBC have real effects on people’s likely votes.
For those who end up watching Fox because of channel position, just four additional minutes of weekly viewing increases the probability of intending to vote for the Republican presidential candidate by 0.9 percentage points. For those who watch MSNBC, four such additional minutes decreases the probability of intending to vote for the Republican presidential candidate by about 0.7 percentage points.
With one hour of viewing per week, the effects are greater. In 2008, an hour of MSNBC decreased the likelihood of a Republican vote by about 3.6 percentage points. In the same year, watching Fox for an hour increased the likelihood of a Republican vote by 3.5 points.
At the level of individual voters, that may not be such a huge deal. But considered across the United States, the effects are large. The researchers estimate that in 2004 and 2008, if there had been no Fox News on cable television, the Republican vote share (as measured by voters’ expressed intentions) would have been 4 percentage points lower. And if MSNBC had had CNN’s more moderate ideology, the Republican share of the 2008 presidential vote intention would have been about 3 percentage points higher. (In general, Fox has more success in converting viewers than MSNBC does; it also has a much larger audience.)
These are disturbingly big numbers. To be sure, Martin and Yurukoglu’s analysis has many moving parts, and the researchers draw some of their key findings from surveys of voting intentions, rather than actual votes. So their particular calculations should be treated as provisional rather than definitive.
Nonetheless, their evidence is the most compelling to date that cable news has a major influence on viewers. Fox News and MSNBC do not merely attract like-minded people. They also heighten divisions among voters, contributing to political polarization – and they have an impact on people’s ultimate votes.
Bloomberg View columnist Cass R. Sunstein, the former administrator of the White House Office of Information and Regulatory Affairs, is a professor at Harvard Law School.