behavioural economics: there are positive feedback loops (things get better => people/companies earn more money => they can borrow more => they spend more => th

behavioural economics: there are positive feedback loops (things get better => people/companies earn more money => they can borrow more => they spend more => things get better) in both directions (things get worse => people/companies earn less => they can borrow less or go bankrupt => they spend less => thing get worse), so even if the underlying events (the external input into the system) are independent and uniformly distributed, the characteristics of the system produce cyclical effects.