I could completely wrong, it is likely that I am, but I think that there are a large number of automated traders on both Bitstamp and BTC-e.  Some while ago these bot-users determined that the Chinese markets could/would serve as nice triggers for the other exchanges.  ++ for a long while it was Gox that served up similar triggers ++

In our increasingly nervous market the bots detect a movement on, say, Houbi and automatically follow suit.  That combination is enough for human traders to climb on the bandwagon and reinforce the initial move.  Then the more rational/reasoned traders counter-move and the initial trajectory is reversed. 

I believe that these oscillations will continue until: 1.  There is no 'other market' that serves up a trigger; or, 2.  Confidence is regained, the nervous market ends, and a true vector forms.

$0.02