I realize that it''s hard enough to get a decent conversation tree for NPCs going, but have been thinking about giving NPCs the ability to lie. Why would an NPC lie? How would an NPC lie? How would PC know if an NPC is lying? How can PC prevent an NPC from lying?

I''ve given this some thought, as I''m also giving my NPCs (and the player) the ability to lie. My ideas on the subject may not be that useful to you, since thay are based on a a design where information takes on an importance greater than I''ve seen in any other game, but here they are anyway in a simplified form...

quote: Why would an NPC lie?

One reason would be to throw the player (or other character) off a trail. For whatever reason (in my case, characters are in competition for the same goals), the NPC may not want the player to locate a certain item. The NPC could decide to try to send the player on a wild goose chase.

quote: How would an NPC lie?

I achieved lying by allowing characters to create a new entry in the information database. This entry represents a false description of the state of the object. Every character attaches his own level of trust to each information node he has access to, and the lying character attaches a trust of zero to this node so that he himself won''t beleive it later on. When it comes time to lie about something, the NPC searches his knowledge base for zero-trust information regarding the object or person, and chooses that information to express to the other character, or creates the zero-trust information at that time if he didn''t do so already.

quote: How would PC know if an NPC is lying?

The PC may have been given bad information earlier by the NPC, checked out that information, and found it to be false. In other words, the NPC may have a reputation or history of being mis-informed or being an out-right liar. Also, if the player knows that the NPC has ulterior motives concerning whatever the player is asking about, the player would be wary of any information provided by that character. And there''s always magic (pretty easy: let the character see the actual trust level of the information being relayed).

quote: How can PC prevent an NPC from lying?

If you allow the player to be able to discern between probable truth and probable lies, as it seems you plan to do from the previous question, I don''t see a need for the player to prevent NPCs from lying.

Sean

quote: Original post by Silvermyst
How can PC prevent an NPC from lying?

Perhaps the PC can develop a reputation for dealing harshly with NPC''s who lie to them. The NPC''s would be too scared to lie to the PC. To make sure the PC doesn''t punish people too much you could have a downside to this reputation, all NPC''s could become afraid of giving the PC information or rumours they''ve heard just in case it''s false.

- DarkIce

Hi Silvermyst

i have given this subject and others involving AI and NPCs alot of thought and i have concluded that it would take alot of Expert AI Programming to get any level of realisim for that kind of thing. so my conclusion is that all the people in the world should be players. just my idea but of course it would have to be in a MMORPG.
if you dont like it i appologize for butting in.

What do you think?



Sir Darkan Fireblade

[edited by - Darkan_Fireblade on May 24, 2002 11:34:26 AM]

I think that to prevent it from being really frustrating, only characters who have a good reason for lying should do so. In other words, the vast majority of people should be totally honest. But if the player speaks to, say, thieves or other people of questionable virtue, where the player would know not to outright trust everything they say, you might have some of them lie. Lies for advancing the plot (spoken by key characters, in other words) are also good, like if an important evil guy lies to you to deceive you.

~CGameProgrammer( );

i dont know the technical terms. just going off rl.

there are two types of lying make sure your system acknowledges that.

there is lying in the form of "i dont know nothing. LOOK. i said i DIDNT see anything. can i go now?"

then there is complete fabrications.

but there are two types of complete fabrications. one type is just to cover the above in a plausible sheath. in the sense you dont want it investigated and you dont want the person to react to it. its like a chemically neutral fabrication.
example:
"My car broke down (fabrication but just to hide the "dont ask me bout it)"

then there is the complete fabrication designed to mislead. this is not a chemically neutral lie. this is something designed to cause reaction in the listener. this is the nemesis in Othello. exampe:
"I saw your girlfriend with ted (lie)"

Consider these three forms of lying when the wife of a thief is confronted:
"Look i said i dont know who know who stole it." (lying ignorance)
"My husband and me were here eating" (lying sheath the facts but no intent to cause reaction)
"I know my husband didnt steal it cause i know Ted stole it here is proof" (lying to cause reaction in audience)


normal people use the first form of lying steadily and constantly. they dont need a reason. they just do. if i dont want to discuss something sensitive with someone that has no business in it i say "i dont know" instead of "i cant discuss that" less of course they are good friends. then i say "look i cant talk bout it"

in games npcs will tend towards the i dont trust you. they will tend to be not so forth right. there is reprecussions. earning their trust is typically the way to get round this.

the second form of lying. the lie design to not cause reaction. specifically designed to hopefully just bury something in its reactionless sheaf is also used by real people. it is typically used when you have some minor debt to the subject being talked about AND the person inquiring has no specific (subjective) business asking bout it.

but i agree the 3rd form is rarely used by most people. it has a evilness to it as old as story. the web we weave when first we plot to decieve. it is that deciet. it is entered into lightly only by fools. its used as a WEAPON in the hands of your npcs. it would only be used thusly if your npcs had reason AND force of will to cause injury.