Regarding the age of volatility that we are now in - what causes volatility in the first place?

For 3 months the Dow chopped around in a range. Before finally closing above 11,600 on friday. My question is, what would make it chop within a certain range for that long a period of time? I can't imagine that would be a chart pattern exhibited by human traders. Humans are chaotic and random.

Is it possible that there are govt sponsored teams out there who's job it is to make sure the dow doesnt fall below a certain level? I picture an infinite govt/fed sponsored bank account attached to a computer that is programmed to buy certain stocks whenever the dow reaches a critical low point. Is this a realistic notion?