“Last week I was outside my office and I saw a $5 bill on the ground. Famously, economists say you never see a $5 bill on the ground because someone would pick it up. But instead of picking it up, I stood around watching to see if anyone else would. A bunch of people walked by not noticing it. Then one guy saw it, saw me, and asked if it was mine. I said no it wasn’t, I was just curious what would happen. He laughed and made a joke about economists. Then a second guy came by, picked it up, and said I’d dropped five dollars. I said no, actually it was there before me. He looked around, noticed a homeless guy across the street, said ‘I think he needs it more than me,’ walked over and gave it to him.” — Matt Yglesias disproves the efficient-markets hypothesis. See also this Dan Gross story from Davos.