I have noticed (and maybe I am wrong) that existing votes of an answer (or question) influence the total votes received.
It is more a philosophical problem of the relation between part and whole
That is probably due to the fact that upvotes or downvotes appear instantaneously.
So when a user clicks a new question existing upvotes or downvotes influence him, until the user shapes his own point of view, and it is probable for him to vote accordingly to previous votes.
I have to mention that there is (in my point of view) a crucial time for the rhythm (of upvoting or downvoting a question or an answer) to be stabilized.
What do you think about total votes appearing after an interval of time, for example, after 5 minutes since the time that have been posted?