Let's say it's election time and I'm on the fence about who to vote for. I see some survey on the news and seeing party A has more vote intentions, it tends to sway my decision towards party A.
Closer to home, I see a question or answer on SE and I may feel swayed to vote +1 or -1 if there are pre-existing votes that have been cast.
What would this phenomenon be called (if there is a name for it other than simple influence or conformity)? Also, can there be a bias for going against what the current trend is?