PHILADELPHIA (CBS) — Simple riddle for you. How do you get a college student to open up?

Offer free pizza.

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And that’s a scientific fact, or at least according to researched findings published in the National Bureau of Economic Research.

Market Watch’s Kari Paul’s report on the study states 98 percent of 3,108 Massachusetts Institute of Technology (MIT) students were willing to give away their friends’ emails when promised free pizza.

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So you see, friends are only as loyal as their last slice.

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For further salt on the wound of no loyalty, 94 percent of students gave up their friends’ emails without any incentives.

But there is a silver lining in all of this.

Within that non-incentives group, 6 percent of them gave fake emails to protect their friends’ identities.

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The next time you order pizza, just remember your friend may be giving out your private information for an extra piece of the pie.