Five years ago, a major U.S. credit card issuer invited me to participate in a panel discussion on the state of the U.S. cards business. My contribution was to tell the assembled executives that the U.S. consumer had done a 180, and that this change would last forever. The average consumer had either lost her job or house during the worst of the great recession, or else knew somebody who did—and this had scared the living daylights out of her. Borrowing patterns would be altered permanently.

A fellow panelist, a prominent consultant in our business and a friend of mine, responded, "Ted, 'forever' is a long time."

He got a lot of nods from the audience. After all, the assembled group had made a living in a business that had been growing at phenomenal rates since 1992. As far as they could see, that growth was based on the U.S. consumer's seemingly slakeless thirst for revolving debt. The economy had hit a snag, they thought, but the U.S. consumer would soon revert to type.

That change has yet to occur, as new research from MasterCard shows. Americans use both credit and debit for different purposes, depending on situational needs. But the lines dividing the functionality and value of debit from credit are now brighter and sharper in consumers' minds.

Between 2006 and 2007, receivables in the credit card industry grew by $79 billion. By contrast, between 2012 and 2013, receivables grew by $11 billion year over year. This suggests a significant decrease in the amount of debt that borrowers are willing to take on.

However, both credit and debit card spending experienced growth in 2013. Credit card spending was up 7.8% from 2012, growing by $174 billion, to approximately $2.4 trillion. Debit card spending also grew by 7.8%, increasing by $158 billion, to $2.1 trillion.

Based on both market research and modeled transaction data tracking consumer attitudes and behavior since 2009, it is safe to assert that consumers have stayed scared—or at least prudent. To truly understand consumers' new financial behaviors, it's necessary to look at how much they are spending, how much they're paying back, and what's going on inside their heads.

Our research shows that Americans today are just as interested in consumer goods, dining out, travel and entertainment as they ever were. They just never want to be in the position they found themselves in at the end of 2008. This creates an interesting dynamic.

The operative truth is that U.S. consumers have deleveraged while continuing, or recovering, their spending. The important thing to note is that U.S. consumers seem to have learned their lesson. Too much debt can get you into trouble. But they still want, and in some cases still need, to spend.

What the psychomarketeers will tell you is that the U.S. consumer has granted herself permission to spend again. But the price of that permission is responsibility. Understand that, and issuers and merchants have an important tool for leveraging consumer behavior in ways that will grow business sustainably—forever, or, at least for another five years.

Theodore Iacobuzio is vice president in charge of Global Insights at MasterCard.