I'm sorry to tell you this, but this is wrong.  The business cycle's root cause is malinvestment.  The social aspect is that, during the boom, investors are as upbeat as everyone else and are more likely to investing borderline projects.  Artificially low interest rates, manipulated by central banks, make this pattern of malinvestment worse but are not themselves the cause.  The root cause of the boom is a form of collective sentiment, what Keynes called "animal spirits".  Keynes was not wrong about the role of the mood of the collective in the business cycle, he was wrong in his belief that it could be forced via monetary policy.  The malinvestment of the boom cycle is what then makes the correction inevitable, but there is always a trigger event that draws the attention of the collective towards the developing cracks in the system.  Once the first true crack is identified to the collective, it starts looking for more, and it finds them; and then the mood changes.  And this continues until the correction resolves the cracks, and the recovery begins.  After a time of no cracks, the sentiment slowly turns to a 'feeling' that there are no more cracks to worry about, and the boom starts again.  In the past, both a gold standard and the more local regionality of the credit & productive markets tended to limit the scope of the boom, and thus the severity of the bust.  The boom from 1992 to 2001 was the longest national (worldwide?) boom period in the history of the US, thus we can expect the most severe correction in the history of the US.  But only once those with the power to manipulate monetary and fiscal policies finally resign to allow the correction to occur, or simply fail to continue to prevent it.