If an NPC is telling the truth, what's the Insight DC to know they're telling the truth?

[5ekyu]

Of course, at times I have asked something like "what would convince your character they were telling the truth?" Or maybe something like "Will this die check convince you they are being truthful?"

If they said "nothing" or "no" then no roll occurs.

 

[AkaKageWarrior]

I don't see why not to use insight checks.
DM info can vary depending on the roll result - which the DM should do.
Possible info:
- you can't tell
- npc seems nervous (which can mean a lot)
- npc is lying
- npc is telling the truth
This depends on the insight vs persuasion or deception roll.

And always give out the info so that the PCs can't be sure...

 

[TaranTheWanderer]

Query: It would seem to me that not looking at the die before announcing the result would remove the uncertainty that you roll the die in order to add; is this a bug or a feature of your approach?

That’s funny. It’s an expression. I just don’t care what the dice result was. I give the player the correct answer but don’t tell them whether they succeeded or failed their insight. They’ll either be satisfied or it will feed into their own paranoia. I leave it to them to play their character however they want.

 

[FrogReaver]

I've been setting it as their 'Passive Deception' DC. What do you do?

If the NPC isn't trying to lie then no roll, simply say there are no signs they are lying. That said, not all NPC's that lie should allow for an Insight check to determine it either. Sometimes their lie is just so good that they tell it so well that no amount of insight is going to be able to determine it's a lie.

 

[Henry]

I would say that a minuscule chance exists for a PC to misread an NPC, even if they are telling the truth. It’s possible, especially if the NPC is normally a very smooth liar. My spot-ruling would be “if the person is familiar to you, it’s an automatic success. In any other circumstance and the NPC is trying to be actually truthful, it’s a DC 5 check.”

And of course, the DC is secret (as well as the roll, depending on DM style).

That way, someone trained in insight is highly unlikely to fail, but there exists a small chance that the very uninsightful might misread the person.

I thought about using “passive deception,” but that’s just too high of a chance, especially for something like that.

 

[Charlaquin]

There appears to be some confusion, you agree with Elfcrusher but then in your example, you provided lying clues thereby treating the Insight skill as a detect lie check. I do understand that you took the "detect lie roll" behind the DM screen which is a step in the right direction, but players will always know a person is lying if you're offering up clues.

No, no. I made a “lie without being detected roll” on the NPC’s behalf, and provide the clue only if that roll fails. Unless maybe you are suggesting that the fact that I rolled a die behind the screen is the clue? In which case, eh. I don’t see that as a big problem. NPCs lying is not the only reason I roll things behind the screen. If the player wants to make that inference, that’s their prerogative. I’m not in the business of policing “metagaming.”

I’m also really big on telegraphing (or “giving players clues.”) My DMing philosophy is that my job is to provide players with the opportunity to make decisions as they think their characters would do. And in order to do so, players need information. The more information they have, the better they feel when their decisions yield good results, and the more accepting they are of their decisions yeilding bad results.

This I believe yields a better result.
Whether the NPC is telling the truth or lying, any failed roll (behind the DM's screen against passive Insight) provides a complication/setback in the fiction.

Well any failed check should always provide a setback or a complication; if it didn’t, it wouldn’t meet all of the requirements for an action’s results to be determined by a check, at least by the way I prefer to run 5e. But I also prefer that every check to be tied to something the character is actively doing. Granted, “I try to see if he’s lying by watching his behavior” is a valid action, but I see it as something the character is doing continuously throughout the course of conversation, not as something they are doing in a specific moment. When you are suspicious of someone, you continuously bwatch them for signs of deception while they are speaking with you, you don’t analyze individual statements to see if they’re lies. Therefore, I feel that a passive check is the best way to adjudicate this, at least for me.

 

[Charlaquin]

That’s funny. It’s an expression. I just don’t care what the dice result was. I give the player the correct answer but don’t tell them whether they succeeded or failed their insight. They’ll either be satisfied or it will feed into their own paranoia. I leave it to them to play their character however they want.

Ah, ok. My mistake, I thought you meant it literally.

 

[TarionzCousin]

If an NPC is telling the truth, what's the Insight DC to know they're telling the truth?

It doesn't matter if my PC's succeed or fail at their roll(s). They'll believe the NPC is lying if they want him/her to be lying. /SMH

 

[Oofta]

I just let them roll, and then tell them something along the lines of "They seem to be telling the truth". Or maybe "They're a bit nervous, but you're not sure why" depending on the situation.

 

[Harzel]

Insight isn't a lie detector, and neither is sense motive in older editions.

When an npc lies, you generally can't tell, unless the DM decides that the npc exhibits a remarkable behavior.

And how does the DM make that decision? To me, it seems that is exactly what the Deception skill is intended for.

And if that be the case, a player can ask wether they can tell what this behavior means... and then (possibly) you roll insight against the npc's deception to determine what it means, but not wether the npc lies. The players may be able to deduce some things that give them a clue regarding whether the npc is telling the truth, but it is still up to them to interpret it how they wish.

For example, an npc might be throwing a suspicious look at someone else at the bar. Determining what that means would require an insight check.
Or, an npc may be making a secret gesture at another npc, again, roll insight.
Or, an npc may be acting a bit skittish or nervous. Determining why he is acting this way, if this can be determined by just looking at him, may require an insight check.
Or, an npc may be bluffing, and the players may ask to check this with an insight check... but maybe it is impossible to determine, that is up to the DM.

Generally speaking, when I have an npc lie to my players, he does so in a way that is not obvious to them at all by any means...

While autofailure is, in the abstract, always one possibility, personally I don't think it makes a very good default independent of circumstances. Can you give any additional insight (haha) as to why you do this?

unless he is really bad at it, and I want him to get caught.

Ok, I assume this is somewhat lighthearted and you really mean that you think he would be caught (regardless of what you might want), otherwise it certainly sounds a bit railroad-ish. Is your procedure in this case to rule an autosuccess or is this the case that you mentioned above in which the NPC would exhibit a 'remarkable behavior'?

Example of insight from play:

DM: While talking to the barmaiden, you notice one of your companions is looking a bit agitated.
Player: Can I tell why she is behaving this way?
DM: Roll insight.
Player: 15!
DM: She seems to be a bit jealous, and about to pick a fight with the bar maiden.
Player: I do not intervene and just enjoy the show.

Example of lying from play:

Npc: One word and I will rain hell down on you and your friends. You are on my turf now, and me and my pals have you vastly outnumbered, surrounded and are better armed. You would do well to lay down your weapons, if you value your lives.
Player: Can I tell if he is telling the truth?
DM: He seems to mean what he says. What are you looking for specifically?
Player: Can I tell if other people in the tavern are on his side?
DM: Make an insight check.
Player: 15!
DM: You notice everyone in the bar is watching you and your friends carefully, and a few shady characters in the tavern seem to have their hands on a weapon tucked underneath their cloak. It seems he is not alone, but whether your party is also outnumbered, you do not know.

I don't understand the distinction between being able to tell if the one NPC is "telling the truth" and being able to tell whether other NPCs are "on his side". To me, these both seem to be instances of being able to discern something about an NPC's mental state. What is it that causes you to treat them differently?