Jonah Lehrer on the psychology of credit cards:
…one of the reasons credit cards are such a popular form of debt is that they take advantage of some innate flaws in the brain. When we buy something with cash, the purchase involves an actual loss – our wallet is literally lighter. Credit cards, however, make the transaction abstract, so that we don’t really feel the downside of spending money. Brain imaging experiments suggest that paying with credit cards actually reduces activity in the insula, a brain region associated with negative feelings. As George Loewenstein, a neuroeconomist at Carnegie-Mellon says, "The nature of credit cards ensures that your brain is anaesthetized against the pain of payment." Spending money doesn’t feel bad, so you spend more money.
The Dish 