Anchoring and credit card minimum payments

"Anchoring" is the psychological effect that, when presented with a sample number prior to being asked to estimate some quantity, people tend to stick closer to that sample number than they would if no number were mentioned, even if the number is completely irrelevant to what's being estimated.

A study by Neil Stewart at Warwick University suggests that minimum payment amounts on credit card bills cause people to pay less on their credit cards per month than they otherwise would, since the minimum payment tends to be extremely low. While it has no effect on those who intend to pay off the full monthly amount (the only reasonable way to use credit cards, in my opinion), Stewart's work suggests that those who pay less than the full amount pay 43% less on average than they would if no minimum payment were specified.

While this might be interpreted as counter to the intent of a minimum payment, I suspect it's exactly the intended effect from the credit card companies--to drag out payments over the longest possible time and accumulate the most interest.