Yes. Here's a video (by youtube user Veritasium) that walks through an experiment and explanation, for those who are interested.

https://www.youtube.com/watch?v=oVfHeWTKjag

From what I've gathered it was humans doing the clicking, of the like of wow gold farmers and captcha resolvers.

But you're right the strategy is not to raise suspicion is to click the targeted ads and like buttons among other random ads and likes.

If I was to learn that facebook was paying those click farms to do the clicking I wouldn't be much surprised.

This is what is happening.