> In our analysis based on 490 roll calls between 2005 and 2014 in the US House of Representatives, we find strong evidence that representatives are more likely to vote with special interests and against constituency interests when the two are in conflict. Importantly, the latter effect is significantly larger when there is less attention on politics.

Speaking of quick Google searches, the quote is from the first result when you search for “Do politicians vote with people's opinion or special interests”.

http://ftp.iza.org/dp11945.pdf