In their book “Firefighting – The Financial Crisis and its lessons” Ben Bernanke, Timothy Geithner and Henry Paulson mention, among other things, how the financial system is principally based on trust. What they call “The Confidence Game” becomes hugely important! One part I think really shows how a bank run mainly operates on human emotion:
A financial Crisis is a bank run writ large, a crisis of confidence throughout the system. People get scared and want their money back, which makes the money remaining in the system less safe, which makes more people want their money back, a self-reinforcing doom loop of fear, fire sales, capital shortfalls margin calls, and credit contractions that can produce a stampede for the exit.
Even if a bank is solid, it still goes back to the “Confidence Game” and perception. A person might see another withdrawing a large amount of money, and think “it doesn’t make sense”; but if the same person sees (or hears about) 10+, 50+ or even 100+ people withdrawing money, they might feel they missed something and will likely take their money out as well. This obviously contributes to the weakening of that institution. Even if the first “rational” step is not to withdraw money, if many act in an irrational way, it can become “rational” to do this as well. In words accredited to John Maynard Keynes: The market can remain irrational longer than the rational investor can remain solvent.
It’s quite interesting to see how much psychology plays in this!