A few weeks after taking an opinion poll, people tweaked their responses to the same questions when they found out a good-looking person would disagree with their original stances. But after learning the date was fictitious and the whole thing was an experiment, the poll-takers couldn’t accurately remember their original answers.

When you lie to impress a potential partner, your dishonesty confuses your memory for the truth, explains study coauthor Sara E. Brady, Ph.D. And whether you’re exaggerating your high school sports achievements or your love of Shakespeare, the more you lie about it, the more your brain will start to accept that lie as fact, Brady adds. That could come back to bite you when your date finds out you were actually a third-string bench warmer who still confuses Hamlet with Macbeth.