1. Sure, using a credit card can be great. You don’t have to carry as much cash around, keeping track of your spending is easier, and credit cards even help you save money. But studies show that cards can also lead you to spend more than you would have with cash.

In 2001, MIT researchers Drazen Prelec and Duncan Simester gave business students a chance to bid on three items: a pair of tickets to a sold-out game between the Boston Celtics and the Miami Heat, a pair of regular-season Red Sox tickets, and a consolation prize of one Celtics and one Red Sox banner. T

2. It turns out that the students were willing to pay 83 percent more on average when paying with a credit card than when paying in cash — and more than twice as much, in some cases. In a second study, simply exposing students to a credit card logo was enough for them to bid more for a gift certificate. That shows that the amount you’re willing to pay in cash isn’t about how much cash you have on hand. There seems to be something intrinsic to credit cards that makes you willing to pay more.

3. Before starting the experiment, the researchers used a sentence-unscrambling task to prime participants to think about either credit cards or cash: Half of them got credit-card words like “Visa," half got cash words like “ATM." Next, they saw a picture of a camera, along with a list of details about its benefits and its costs, then they were asked to recall as many of those details as possible. Those primed to think about credit cards made significantly more recall errors about the cost attributes than the cash-primed participants.

Why is this? When you pay with cash, you’re physically giving up a handful of bills, so you’re forced to think about the amount. But it’s all too easy to mindlessly swipe your card when an amount is just a number, and you have until the end of the month to deal with your spending.