I’d bet money on the fact that everybody lies to some degree, even if they genuinely don’t know they are doing it. It’s part of what we are in my honest opinion. You have to teach kids not to lie, the act of telling porkies comes naturally.
I read a great book on this subject called ‘the philosopher and the wolf’a few years back. The crux of which was that it’s the ability to deceive that differentiates us and the other apes from the rest of the animal Kingdom. A good read and a good argument.