Caught red-handed and still lying

Back in college, one of my friends dated a guy named Jason. We all thought he was a pretty cool guy, nice and fun to hang out with. That is, until his girlfriend contacted my friend and informed her that he was playing both of them.

Some quick Internet sleuthing confirmed her story. My friend, who unknowingly became "the other woman," confronted Jason. He denied everything. She laid out all the evidence of his cheating ways, and he still had the gall to look her in the eye and lie to her. Ridiculous. Since my friend's a smart girl, she stopped seeing him, of course.

It baffles me why some people continue to lie after being caught -- with pretty hard evidence no less. An answer to a question posed on www.truthaboutdeception.com, offers some insight to why this is:

From your husband’s point of view there are two possible outcomes: 1) lie about what happened with the hope of diffusing your anger with confusion. Or he can 2) tell the truth and get punished even more.

By nature, people are designed to avoid punishment – often resorting to telling lies when necessary to do so. Often this is an unconscious response, which is developed early in life (see, lying comes easy). Given this dynamic, it is easy to understand why most cheating spouses lie, even when confronted with evidence of their actions.

I'm a little dissatisfied that the answer basically says that it's human nature to lie, but I guess that goes back to the innate aim of self-preservation.

Have you ever caught someone in a lie and they continued lying? What did they lie about? How did you respond? Have you ever been caught in a lie and kept lying to try to ward off punishment? Why do you think some people continue to lie even after being caught?