One of the important elements of the plans for Trivial Bullshit (as outlined here) is the mechanic by which it’s determined whether a player will lie in answer to the question posed in a round, or tell the truth.
In deciding how this would work, we initially discussed whether a system like that was needed. We realised early on that it would be necessary: if it was left up to the players to make the choice between truth/lie on their own, it’s possible that there would be multiple people attempting to use the true answer, which would muddle the competition and point allocation. So, like in games like Mafia, we needed players to be forcibly assigned a role that they would have to stick to for the round if they wanted to win.
The simplest solution for this problem was a small deck of cards, enough for one per each player who has to give an answer in a round. These cards are marked TRUTH and LIE, and in every game’s hand, there has to be one (and only one) TRUTH card. This is because the purpose of the game is for the questioning player to discern the truth, not to prove their trivia knowledge: for this to work, there needs to be a true answer available for them. However, each answer provided also needs to be unique so that players have room to argue for why their answer makes the most sense. There can’t be more than one TRUTH card, because if the same answer turned up twice in a round, it would be obvious to the questioning player that the duplicate answer had to be the real one. So the only configuration that works is one TRUTH card, and enough LIE cards to be distributed to the rest of the players.
A part of the rules we haven’t discussed yet that we integrated in the playtesting is that players aren’t allowed to use the reason “I drew the TRUTH card” in their argument for why they have the most believable answer. It seemed to go without saying when we playtested; the player with the TRUTH card would never justify themselves by simply saying, “this answer is the truth because that’s my assigned role” and instead tried to argue with reasoning the same way they would if it were a lie. In one round, this unspoken rule made the true answer seem even more unconvincing than the lies, because the truth-teller couldn’t come up with any way to make their answer sound reasonable. This was definitely the best result, and it’s something that needs to be put in the rules to make sure it’s a part of the game experience.