While this is an old image, the pattern was very much used between 6000 and 7000 and also somewhat between 3000 and 4000.
Obviously, the reason are short-term traders. But they have the same effect than as if was a "FED" - they've stabilized the price a bit. So encouraging short-term trading techniques (including arbitrage and short-term short selling) seems a viable strategy to stabilize the Bitcoin price and make it more useful "as a currency"
(I'm still working on the idea I linked before. Maybe this year I can code a prototype. However, it seems this year is to become bullish, so it wouldn't get massive acceptance, but at the end of a bull phase stabilization mechanisms will get more demand (as people become increasingly fearful) )
FYI
We hired a person, to be the CEO of our FED:
I would like to present his face:
I just met with he on the bitcoinwisdom. Bitstamp.