Want proof? Consider an experiment conducted several years ago by Drazen Prelec and Duncan Simester, marketing professors at the Massachusetts Institute of Technology in Cambridge, Massachusetts. The pair organized a real-life, sealed-bid auction for tickets to a Boston Celtics game (this was during the Larry Bird, Kevin McHale, Robert Parish era, so the tickets were especially valuable). Half the participants in the auction were informed that whoever won the bidding would have to pay for the tickets in cash (although they had a day to come up with the funds). The other half were told that the winning bidder would have to pay by credit card. Prelec and Simester then averaged the bids of those who thought they would have to pay in cash and those who thought they could pay with a credit card. Incredibly, the average credit card bid was roughly twice as large as the average cash bid.