Why can't you make the entire system easier. There should be only an UPARROW so you click if the information is related and valuable. Then have a separate like and dislike counter, BUT has no other weight except just a visual of how likable it is.

For example: ^30 Like(30) | Dislike (30)

The point is that people react through visual familiarity. We are to condition to see the UP and DOWN arrows as positive and negative.