SouthEastPatriot

Trapped by Design? The Prisoner's Dilemma and Traditional Banking The prisoner's dilemma is a thought experiment from game theory, formalized in the 1950s. Two suspects are arrested and held in separate rooms, unable to communicate. Each is offered the same deal: If both stay silent (cooperate), they each get a light sentence. If both betray each other (defect), they each get a moderate sentence. If one betrays and the other stays silent, the betrayer walks free and the silent one gets the harshest sentence. The payoff table looks something like this: Look at it from one prisoner's point of view. Whatever the other person does, betraying gives you a better individual outcome than staying silent. If they stay silent, betraying gets you freedom instead of a year. If they betray, betraying gets you 5 years instead of 10. Betrayal is what game theorists call a dominant strategy and it's the better choice regardless of what the other player does. The catch is that both players reasoning this way land in mutual betrayal... 5 years each, when mutual cooperation would have gotten them 1 year each. Two individually rational choices produce a collectively worse outcome than the one that was actually available. That gap between individually rational and collectively rational is the whole point of the dilemma, and it shows up anywhere people can't fully trust or coordinate with each other but share a common fate. Why banking structures produce this exact shape A modern bank doesn't hold your deposits in a vault. Under fractional reserve banking, it keeps a fraction on hand and lends most of the rest out to mortgages, business loans, other depositors' withdrawals. This works fine as long as depositors don't all want their money back at once. It depends on cooperation: everyone quietly trusting the system enough to leave their money in. That's a real prisoner's dilemma, not just a metaphor for one. If you trust the bank and leave your money in, and everyone else does too, the system functions and you get your modest interest. But if you suspect others might pull their money out, your individually rational move is to withdraw first... because the bank literally cannot pay everyone at once. This is the mechanics of a bank run... each depositor's dominant strategy, once doubt creeps in, is to defect before the others do, and the collective result is a run that can take down a solvent institution. It happened to regional banks as recently as 2023 (Silicon Valley Bank, Signature Bank), where uninsured depositors moved in hours, not days, because the individually rational move was obvious and everyone could see everyone else reasoning the same way. I thought it would be handy to outline The Prisoner's Dilemma, before delving into @hashdag's prefered model, which is the Stag Hunt. If you enjoyed this, you should definitely check out the full interview with @hashdag youtube.com/live/l_v3Mr5vigQ…