This might possibly make some sense of my general view that I have about lying, which is that it's not quite as simple as "honest people" and "dishonest people". I'm sure there are some people who are truly dishonest, in that they've thought very clearly about what the truth is and are being intentionally deceptive. However, I know a number of people where I'd be more inclined to say that they're just not really thinking about it.
That might sound weird or a little nonsensical, but what I mean is, there's a certain level of mental activity to "be honest". It's not just about the courage to voice your opinion, but also whether you go through a certain kind of thought process. To give a common example, if you ask your coworker, "How are you doing?" there's a decent chance that person will say, "Good" without even thinking about it. They might be miserable, but it's not necessarily an intentional deception. Maybe you're just being polite, or you don't want to share. Or maybe you're just responding because that's the proper conventional response to the question.
To give a slightly more complex example, if I ask what your favorite movie is, you might just say "Pulp Fiction" even though that's not your favorite movie. Maybe it's a movie that came to mind that you liked. Maybe it was a movie that your decided was your favorite movie well over a decade ago, and you've just used that as your answer when people ask, even though there are other movies you like better. Or maybe you said "Pulp Fiction" just because you thought it was a good answer that other people would agree with.
I used to think that it was as simple as "being honest" or "being dishonest", but I've realized over the years that a lot of times, we just end up giving whatever answer is quick and easy, or the safe answer that won't cause trouble. Some people do it more than others, and I've known a few people for whom communication isn't really about conveying information, but more about social maneuvering. And I don't even mean that it's malicious, since it may be as innocent as just saying whatever will get you to like them and make everyone get along. I think it's not even necessarily an intentional deception, but instead it's more like they're not even thinking about the truth content of their answer in the context of "true" or "false", but more like "achieves the desired effect" or "doesn't achieve the desired effect".
So I'm rambling a little, but I wonder if the amygdala has a role in the evaluation of truth content. If my general thought is correct, it'd be reasonable to think that there's some part of the brain with is being under-used in people who "end up giving whatever answer is quick and easy".