When I see both an up and a down arrow next to a comment and I zoom in so that I can touch just one of them it seems the other one lights up as well. At least t

When I see both an up and a down arrow next to a comment and I zoom in so that I can touch just one of them it seems the other one lights up as well. At least that is my impression on the iPhone. So do these little tiny arrows really vote up and down or are they just a neutral engagement signal? I always intended to look in the code but as it fits this topic, I guess I can just as well ask here.