But lying is a lot more than simply not telling the truth, or saying something that isn't true. Lying causes people to think and behave differently, whether they realize it or not. We want to explore that in our lying characters.
But as writers, we hopefully don't know that much about lying. I'd like to think that we don't lie ourselves very often, and that we don't hang out with a bunch of people who lie all the time. So how do we get real experience on people lying to each other (especially when they're not going to just tell us that they're lying)?
The popular party game, Mafia, involves a small number of the players secretly conspiring to kill all the other ones. They privately, silently kill someone, and when the death is revealed, everyone in the game bands together to decide who to lynch under suspicion of being mafia. The mafia members will do very interesting things to avoid suspicion and get the town (everyone but mafia) to lynch another town member instead of a mafia member.
Whenever someone dies, you learn what their role was, and whether or not they were lying. By looking at some standard mafia strategies, we can use similar pathology to flesh out our deceitful characters (or send truth-seekers down more interesting paths.)
I played a game of mafia online recently, in a forum dedicated solely to these games. I was a mafia member, and at first I thought this would be easy--all I have to do is pretend to be a townie and act accordingly, right? But they dissected every one of my posts to reveal certain behaviors that logically pointed to me being mafia, even though I had no idea they were there. This forum had developed a list of sayings and acronyms that everyone knew, all describing some common mafia behaviors. These are also called scumtells. I've listed them below, and with each scumtell, I have a suggestion for a potential application in our writing.
1. WIFOM - Wine In Front Of Me
WIFOM (a term from the classic scene in The Princess Bride) is an argument based on the hypothetical. Such as, "Now, a clever man would put the poison into his own goblet, because he would know that only a great fool would reach for what he was given," or, "If I were mafia, I wouldn't have tried to keep us from lynching that one innocent guy we lynched last night." These are arguments based on assumptions. A liar will often engage in WIFOM because they subconsciously know that they're actually guilty in real life, and so they make false arguments based on a hypothetical world where the operating assumptions don't involve them being mafia. Mafia will often do this without realizing it (I did), but innocent people also do it all the time just because they have bad logic.
Readers will identify someone as suspicious pretty quickly if they defend themselves with assumptions. If you want a red herring character you'd like your readers to suspect, have them engage in some WIFOM, only to learn later that that person was just using bad logic and often operates on assumptions in their normal life. Alternatively, you can have a liar engage in WIFOM but not have the reader realize it if the reader (or main character) doesn't realize that their operating assumption isn't true. Have a character with an air-tight alibi that removes them from early suspicion, only to reveal later in your story that their alibi was based on something that wasn't actually true (ie, they have a stamp on their passport for a specific country, but you learn that country was closed to all non-nationals that week).
2. OMGUS - Oh My Gosh You Suck
OMGUS occurs when you attack, or even vote for the person who attacks or votes for you. It's petty, emotional, and doesn't further any logical discussion. Mafia will do this when they don't want to bother accusing someone based on logic (again, they know that that person isn't mafia and so they're afraid of using actual logic), so they use the excuse of being petty.
I think this is more ripe material for red herrings. Liars will often lash out at whoever accuses them of lying--but so do petty people. Readers also will think distastefully of petty characters and be more likely to think of them as harboring other negative attributes (such as being deceitful or having murderous tendencies). In the end, these people just might be petty, or have an over-defensive nature because of some experiences in their past where they've been unjustly accused, or perhaps they really do have something to hide--just not the fact that they're the murderer.
Based on a term describing people who regularly visit an online community but almost never participate, lurkers in mafia are those who don't forward any arguments at all--they just listen silently. The thinking here is that mafia have more to lose by talking, because they might accidentally reveal bad logic or other scumtells. If everyone stays silent, then when the town decides to lynch someone it will be almost random, odds that are good for the mafia players.
Liars won't volunteer much information, even if that information has absolutely nothing to do with their lie. They suspect any innocent question as the beginning of an interrogative line of questioning and will try to cut this off as much as possible. In the novel I'm working on right now, my main character has decided to lie to two survivors as to where he's taking them. He becomes paranoid about any questions they ask him and won't volunteer any information at all, spending most of their travel in silence--partly because of his nature, but also because he's trying to contain a lie. As far as Whodunit structure goes, characters who are silent, non-participatory, or peripheral make for unsatisfying reveals at the end, in my opinion. There's not much mystery if the killer is the guy who fled the scene of the crime and hides from everybody the whole time. And it's not satisfying if it turns out to be the rich uncle who is only present in the story via other characters talking about him. I like for the reveal at the end to not just reveal the mystery, but to also reveal something about the character of the killer. Who cares what it reveals if the reader never got a chance to get to know that character throughout the course of the story? The reader sure doesn't.
4. Congratulating the Medic
In mafia, there is sometimes a medic who can try to guess who the mafia will try to kill, and then preemptively "save" them. When it's revealed that the mafia tried to kill someone but that the medic prevented the kill, mafia will sometimes try extra-hard to be happy about this news, congratulating the medic on a good defensive read. This is a scumtell because it illustrates overcompensation on the part of the liar, who is secretly feeling frustration and disappointment that their hit missed. When people want to hide a powerful emotion, it's harder to cover it with a mask of moderate emotion than it is to simply switch to that emotion's powerful opposite. So mafia will try to look gleeful when things are actually awful for them.
If your character is masking a lie, he may find himself wearing a more garish mask than necessary. "Wow, I can't wait until I take you guys to the super-awesome Eden-like paradise I told you about! It's definitely not going to be a human-ranch for vampires!" Nothing so obvious, of course. However, note that readers pick up on this easily, and other characters will at least note the liar's exuberance. Characters who go out of their way to check up on the detective's progress and offer encouragement and sympathy, such as the scientist in BBC's The Hounds of Baskerville, may very well be overcompensating.
5. Change in Behavior
In the online mafia forum I played this game, a lot of the veterans had played a large number of games together and knew each other's general play styles. So they'd search someone's post history and get suspicious when that someone was posting more frequently/infrequently or using different logic patterns. If people know each other better, it's easier to tell when they're lying--not just because of experience watching them lie, but experience in knowing how they normally act.
When someone lies, they're not just not telling the truth--they change, as a person. They try to rewrite themselves as people and don't quite know how to behave anymore. If your character lives a lie for a long time, they probably won't have a firm self-identity (except as a liar), or suffer a lot of self-delusion. If a character starts a new lie, their behavior will change, and those who know that person well will notice the change.
6. Wolf In Sheep's Clothing
This is what I tried to do in my game of mafia. I attempted to be as active as possible, forming arguments and defenses left and right, behaving as much like a townie as possible. While the town was suspicious of all the lurkers because of their silence, it took them quite a while to suspect one of the most active players, myself. (When they did finally point the finger at me, I engaged in a WIFOM defense: "If I were mafia, why would I do XYZ?") It's simultaneously harder to suspect an active player while also easier to analyze if they're guilty because of their high post content.
I think this is the most interesting kind of liar. They're not passive, hoping to be passed over, but actively influencing the investigation/plot towards red herrings and other bad leads. The liar is actually performing as an antagonist to the mystery-solver. Imagine if the killer isn't the one who fled the scene of the crime, or the overly-defensive aunt, or the petty grandmother, but the helpful Watson figure who sends the detective down all those avenues. When the reveal happens, you re-examine the entire story as well as the main character relationship. I feel that this kind of liar is the hardest to write, but the most rewarding to experience as a reader.
Sorry this was such a lengthy post, but I think that deceit is such a prevalent and difficult story element, and that you can learn a lot by looking at these scumtells. Also, note that while I use Whodunit plots as an example multiple times, the concepts of mystery enter all kinds of fiction, and these principles should still translate well.