Why you can't stop shopping

By Steve Kastenbaum, CNN

Follow on Twitter: @SkastenbaumCNN

Editor's Note: Listen to the full story in our player above, and join the conversation in our comments section below.

(CNN) – Did you spend more than you budgeted for while shopping for holiday gifts this year? If yes, is that because you bought some stuff for yourself, too?

There's a good chance that once you bought that first item, you couldn't stop yourself from buying more.

“Once a shopper makes that first purchase they, in a sense, have pulled their finger out of the dyke," said consumer psychologist Bruce Sanders. "They have been holding on and feeling that they don’t want to spend too much. And now that finger comes out of the dyke and then they get into a purchasing momentum. They go with the flow.”

Sanders says once a shopper is in the flow state, a few other things happen that make you want to continue shopping without worrying about how much you are spending.

“It's the enjoyment of activities for their own sake. So you’re enjoying the shopping experience and, therefore, there’s a hesitation to stop shopping. And to top it off, there’s a distorted sense of time when a person is in that flow state. So they’re less concerned about how long the shopping trip is going to take.”