I wrote a post about this exact issue yesterday, where some scientists quantified the effect of copycat behaviors in a study of song popularity, somewhat simplified by having no bots and no financial rewards. If people have social information, they will use it.
https://steemit.com/steemit/@plotbot2015/experimental-proof-that-the-quality-of-your-posts-does-matter-some
I post it again here because of bot-voting. I had easily twice the number of unviewed votes as viewed votes, so even though some here may have voted for it, they may not have read it.
They didn't address the tagging issue, but the same process underlies it. People copy what seems successful. The only way to deal with that is structurally. One way to do that is by reducing the number of tags. I say that despite the fact that I personally like multi-tagging, because I like writing things that really are science and sf and comics, for instance. Even I have a hard time coming up with five tags for every post. Usually I fill in with one of the curation projects.