The price of dirty money Be careful the next time you handle dollar bills that aren’t crisp and clean—they might actually cost you. In a series of experiments, psychologists found that dirty-looking money leads to dirty ethics. People who handled, or read about, dirty bills behaved more selfishly and were less concerned about reciprocity and fairness. It wasn’t the dirt alone that caused this debasement; handling dirty paper other than money actually made people more ethical. It was the combination of dirt and money that mattered. The researchers found this was true in the real world as well: After being presented …

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