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''This house rule allows users of Detect Lies to make their own rolls, which some players enjoy.  This house rule also includes information on using lie detection equipment.  If you consider Detect Lies to be a cinematic skill, this house rule renders it less so.  (If you like this house rule, you might also be interested in my Interrogation house rule.) ''
''This house rule allows users of Detect Lies to make their own rolls, which some players enjoy.  This house rule also includes information on using lie detection equipment.  If you consider Detect Lies to be a cinematic skill, this house rule renders it less so.  (If you like this house rule, you might also be interested in my [[Interrogation]] house rule.) ''


===Detect Lies===
'''Per/Hard''' <br>
====Per/Hard====
<span style="color:fuchsia"> ''Defaults:  Perception-6, Body Language-4, or Psychology-4'' </span>
<span style="color:fuchsia"> ''Defaults:  Perception-6, Body Language-4, or Psychology-4'' </span>


This is the ability to determine if somebody is lying by observing and interpreting physiological changes and psychological mannerisms.  
This is the ability to determine if somebody is lying by observing and interpreting physiological changes and psychological mannerisms.  


A successful Detect Lies roll means you noticed a tell that indicates the person either lied or told the truth.  The potential liar, however, gets a chance to defend using Acting or Fast Talk (or an IQ-5 default).  If the liar makes his roll by more than you made your Detect Lies roll, the GM will give you an answer that favors the liar--you misinterpret a tell or believe a false one.  An unsuccessful Detect Lies roll means you do not pick up any tells or they’re inconsistent.  A critical failure means that person is particularly hard for you to read for some reason and you don’t trust yourself to reliably interpret their tells for the rest of that encounter.  A critical success on your part or a critical failure on their part indicates the revelation of additional and/or unexpected information.  Because of this game mechanic, PCs can be allowed to make their own Detect Lies rolls.  WARNING: Under this house rule, a career liar will often fool you.  
===Detect Lies vs Acting===
A successful Detect Lies roll means you noticed a tell that indicates the person either lied or told the truth.  The potential liar, however, gets a chance to defend using Acting (but not Fast-Talk).  If the liar makes his roll by more than you made your Detect Lies roll, the GM will give you an answer that favors the liar--you misinterpret a tell or believe a false one.  An unsuccessful Detect Lies roll means you do not pick up any tells or they’re inconsistent.  A critical failure means that person is particularly hard for you to read for some reason and you don’t trust yourself to reliably interpret their tells for the rest of that encounter.  A critical success on your part or a critical failure on their part indicates the revelation of additional and/or unexpected information.  Because of this game mechanic, PCs can be allowed to make their own Detect Lies rolls.  WARNING: Under this house rule, a career liar will often fool you.  


Detecting lies with lie detection equipment requires having spent at least 1 character point on Electronic Operations (Medical) skill.  Lie detection equipment becomes available at TL 6 and gives a bonus to Detect Lies skill equal to your margin of success with Electronic Operations (Medical) skill, up to a maximum of TL-5 or your relative skill level, whichever is less.  The person lying can resist with Body Control by regulating the normally involuntary physiological changes that occur when they lie.  This is a regular contest, Electronics Operations (Medical) vs. Body Control.  (Option: a good Actor without Body Control skill may be able to get into character enough that they, for all intents and purposes, adopt a new personality that is consistent with their lie.  This is very difficult and amounts to a -7 penalty to their Acting skill.)  When using lie detection equipment, you may make one Detect Lies vs. liar roll for the entire session if you wish.  I.e. you ask all your questions then go over the results of the polygraph later.
{| align="center" border="1"
|+ '''Detect Lies vs Acting'''
!
! Acting Roll Succeeds By More
! Acting Roll Succeeds By Less or Fails
|-
! Detect Lies Roll Succeeds
| You incorrectly interpret a tell || You correctly interpret a tell
|-
! Detect Lies Roll Fails
| You don't pick up any reliable tells || You don't pick up any reliable tells
|-
|}


An attempt to Detect Lies accurately under any circumstances requires you to get a feel for the tells of a particular individual; this takes 25 minutes for a total stranger.  Apply a reduced time penalty of -1 for every 5 minutes you fall short of the requisite time.  For a first-time subject and no time you start at a -5 penalty.  This means that, if possible, you should spend 25 minutes of quality time with a stranger before you use Detect Lies.  
An attempt to Detect Lies accurately requires you to get a feel for the tells of a particular individual; this takes about 30 minutes for a total stranger.  For a first-time subject that you've just met, you start with a -5 penalty.  Lessen this penalty by 1 for every 5 minutes of quality time you spend with the subject.  This means that, if possible, you should spend about a half hour conversing with a stranger before you use Detect Lies.


Modifiers: +1 for Sensitive or +3 for Empathy (p. B51), or -3 for Low Empathy (p. B142); +4 if your subject is Easy to Read (p. B134).  If the subject is of a different species, the GM may assess a penalty - see Physiology Modifiers (p. B181).  Up to a TL-5 bonus with lie detection equipment.  Up to a -5 penalty due to reduced time.  (The liar may also receive bonuses.  If an Actor has time to prepare, give them a +5 bonus. If a Fast Talker is saying little more than “yes” and/or “no”, give them a +5.)
If the liar has time to prepare his story--at least 30 minutes to "get his story straight"--he may get up to a +5 bonus.


'''Example 1''': with lie detection equipment:
===Electronic Operations (Medical) vs Body Control===
You have IQ 11, Detect Lies at 15, and Electronic Operation/TL9 (Medical) at 12; a con man, who has had ample to to prepare his story, has Acting at 17.  Your Electronic Operation/TL9 (Medical) roll is a 9 (made by 3) and the con man’s Acting roll is a 13 (made by 4--not enough to overcome the -5 modifier); you win the regular contest for getting a lie detection equipment bonus of +1 (your relative skill level)After spending half an hour with the grifter hooked up to lie detection equipment, you roll against your Detect Lies+1If you miss, the lie detection results are inconclusive; if you succeed, the con man (we’ll assume he lies) gets an Acting+5 rollIf he succeeds by more than you, then he appeared to be telling the truth; otherwise, he appeared to be lying.  You get a +1 because of the lie detection equipment; he gets a +5 because he had time to get into character.  It would be appropriate to make the number of lies caught dependent on how successful your roll was and/or how unsuccessful his roll was.  
Detecting lies with lie detection equipment requires having the Electronic Operations (Medical) skill.  Lie detection equipment becomes available at TL 6 and gives a bonus to Detect Lies skill equal to your margin of success with Electronic Operations (Medical) skill, up to a maximum of TL/2The person lying can resist with Body Control by regulating the normally involuntary physiological changes that occur when they lie.  This is a regular contest, Electronics Operations (Medical) vs. Body Control(Option: a good Actor without Body Control skill may be able to get into character enough that they, for all intents and purposes, adopt a new personality that is consistent with their lie.  This is difficult and amounts to a -5 penalty to their Acting skill if they've had time to prepare (30 minutes minimum); if they haven't had time to prepare, the penalty is -10.


'''Example 2''': without lie detection equipment:  
{| align="center" border="1"
At TL5 you ask a working women in a saloon her age and want to know if she’s telling you the truth.  You have Detect Lies skill at 12; she does not have Acting or Fast Talk skill.  This is a contest of your Detect Lies-5 vs her IQ.  You take full reduced-time penalties in a situation like this; she gets a +5 bonus to her IQ-5 default for this easy lie.  After about of half hour of conversation and observation, you could ask again(Some GMs will assess a penalty for a repeated attempt.) Indeed, it is difficult to know with certainty when you are being lied to by a stranger in a social situation.
|+ '''Electronic Operation (Medical) vs Body Control'''
!
! Body Control Roll Succeeds By More
! Body Control Roll Succeeds By Less
! Body Control Roll Fails
|-
! Electronic Operation (Medical) Roll Succeeds
| You gain no bonus || You gain a bonus equal to your margin of success less their margin of success up to a maximum of TL/2 || You gain a bonus equal to your margin of success up to a maximum of TL/2
|-
! Electronic Operation (Medical) Roll Fails
| You gain no bonus || You gain no bonus || You gain no bonus
|-
|}
 
When using lie detection equipment, you may make one Detect Lies vs. liar roll for the entire session if you wish.  I.e. you ask all your questions then go over the results of the polygraph later.  If you are working alone, this is the preferred method, as questioning while trying to actively interpret the lie detection equipments output would result in a -1 multitasking penalty to either your Detect Lies or Electronic Operation (Medical) skill.
 
===Modifiers===
* +1 for Sensitive or +3 for Empathy (p. B51)
* -3 for Low Empathy (p. B142)
* +4 if your subject is Easy to Read (p. B134)
* If the subject is of a different species, the GM may assess a [[Interspecies Defaults|penalty]] - see Physiology Modifiers (p. B181).
* Up to a TL/2 bonus with lie detection equipment.
* Up to a -5 penalty due to reduced time.  Reduce penalty by 1 for every 5 minutes.  Taking extra time [B346] (beyond 30 minutes) can give a bonus.
* The liar may also receive bonuses; up to a +5 bonus if they've prepared for 30 minutes or more.  (This means non-Actors that are prepared roll against their IQ.)
 
==='''Example 1''': With Lie Detection Equipment===
You have Detect Lies at 15 and Electronic Operation/TL9 (Medical) at 12; the con man has Acting 17 and has had ample time to prepare his story.  Your Electronic Operation/TL9 (Medical) roll is a 9 (made by 3) and the con man’s Acting-5 roll is a 13 (missed by 1); you win the contest and the lie detection equipment gives you a bonus of +3 (your margin of success).  After spending half an hour with the grifter hooked up to lie detection equipment, you roll against your Detect Lies+3.  If you fail, your lie detection efforts are inconclusive; if you succeed, the con man (we’ll assume he lies) gets an Acting+5 roll.  If he succeeds by more than you, then he appeared to be telling the truth; otherwise, he appeared to be lying.  You get a +3 because of the lie detection equipment; he gets a +5 because he had time to craft his story.  It would be appropriate to make the quality and quantity of lies caught dependent on your margin of successful in the contest.
 
==='''Example 2''': Without Lie Detection Equipment===
At TL5 you ask a working women in a saloon her age and want to know if she’s telling you the truth.  You have Detect Lies skill at 12; she does not have Acting skill.  This is a contest of your Detect Lies-5 vs her IQ-5.  You take full reduced-time penalties in a situation like this.  After about of half hour of conversation and observation, you could ask again (at a -2 penalty this time, for a repeated attempt).  Indeed, it is difficult to know with certainty when you are being lied to by a stranger in a social situation.
 
==See Also==
 
[[2d Damage]] optional | [[Combat Maneuvers]] | [[Interrogation]] | [[Meditation]] | [[Stealth]] |  [[Tactics]]
 
[[GURPS SPACE: Star Trek: Aurora |STA main page]]
 
 
[[Category: Image's House Rules]]
[[Category: STA Player Information]]

Latest revision as of 05:59, 1 May 2010

This house rule allows users of Detect Lies to make their own rolls, which some players enjoy. This house rule also includes information on using lie detection equipment. If you consider Detect Lies to be a cinematic skill, this house rule renders it less so. (If you like this house rule, you might also be interested in my Interrogation house rule.)

Per/Hard
Defaults: Perception-6, Body Language-4, or Psychology-4

This is the ability to determine if somebody is lying by observing and interpreting physiological changes and psychological mannerisms.

Detect Lies vs Acting

A successful Detect Lies roll means you noticed a tell that indicates the person either lied or told the truth. The potential liar, however, gets a chance to defend using Acting (but not Fast-Talk). If the liar makes his roll by more than you made your Detect Lies roll, the GM will give you an answer that favors the liar--you misinterpret a tell or believe a false one. An unsuccessful Detect Lies roll means you do not pick up any tells or they’re inconsistent. A critical failure means that person is particularly hard for you to read for some reason and you don’t trust yourself to reliably interpret their tells for the rest of that encounter. A critical success on your part or a critical failure on their part indicates the revelation of additional and/or unexpected information. Because of this game mechanic, PCs can be allowed to make their own Detect Lies rolls. WARNING: Under this house rule, a career liar will often fool you.

Detect Lies vs Acting
Acting Roll Succeeds By More Acting Roll Succeeds By Less or Fails
Detect Lies Roll Succeeds You incorrectly interpret a tell You correctly interpret a tell
Detect Lies Roll Fails You don't pick up any reliable tells You don't pick up any reliable tells

An attempt to Detect Lies accurately requires you to get a feel for the tells of a particular individual; this takes about 30 minutes for a total stranger. For a first-time subject that you've just met, you start with a -5 penalty. Lessen this penalty by 1 for every 5 minutes of quality time you spend with the subject. This means that, if possible, you should spend about a half hour conversing with a stranger before you use Detect Lies.

If the liar has time to prepare his story--at least 30 minutes to "get his story straight"--he may get up to a +5 bonus.

Electronic Operations (Medical) vs Body Control

Detecting lies with lie detection equipment requires having the Electronic Operations (Medical) skill. Lie detection equipment becomes available at TL 6 and gives a bonus to Detect Lies skill equal to your margin of success with Electronic Operations (Medical) skill, up to a maximum of TL/2. The person lying can resist with Body Control by regulating the normally involuntary physiological changes that occur when they lie. This is a regular contest, Electronics Operations (Medical) vs. Body Control. (Option: a good Actor without Body Control skill may be able to get into character enough that they, for all intents and purposes, adopt a new personality that is consistent with their lie. This is difficult and amounts to a -5 penalty to their Acting skill if they've had time to prepare (30 minutes minimum); if they haven't had time to prepare, the penalty is -10.)

Electronic Operation (Medical) vs Body Control
Body Control Roll Succeeds By More Body Control Roll Succeeds By Less Body Control Roll Fails
Electronic Operation (Medical) Roll Succeeds You gain no bonus You gain a bonus equal to your margin of success less their margin of success up to a maximum of TL/2 You gain a bonus equal to your margin of success up to a maximum of TL/2
Electronic Operation (Medical) Roll Fails You gain no bonus You gain no bonus You gain no bonus

When using lie detection equipment, you may make one Detect Lies vs. liar roll for the entire session if you wish. I.e. you ask all your questions then go over the results of the polygraph later. If you are working alone, this is the preferred method, as questioning while trying to actively interpret the lie detection equipments output would result in a -1 multitasking penalty to either your Detect Lies or Electronic Operation (Medical) skill.

Modifiers

  • +1 for Sensitive or +3 for Empathy (p. B51)
  • -3 for Low Empathy (p. B142)
  • +4 if your subject is Easy to Read (p. B134)
  • If the subject is of a different species, the GM may assess a penalty - see Physiology Modifiers (p. B181).
  • Up to a TL/2 bonus with lie detection equipment.
  • Up to a -5 penalty due to reduced time. Reduce penalty by 1 for every 5 minutes. Taking extra time [B346] (beyond 30 minutes) can give a bonus.
  • The liar may also receive bonuses; up to a +5 bonus if they've prepared for 30 minutes or more. (This means non-Actors that are prepared roll against their IQ.)

Example 1: With Lie Detection Equipment

You have Detect Lies at 15 and Electronic Operation/TL9 (Medical) at 12; the con man has Acting 17 and has had ample time to prepare his story. Your Electronic Operation/TL9 (Medical) roll is a 9 (made by 3) and the con man’s Acting-5 roll is a 13 (missed by 1); you win the contest and the lie detection equipment gives you a bonus of +3 (your margin of success). After spending half an hour with the grifter hooked up to lie detection equipment, you roll against your Detect Lies+3. If you fail, your lie detection efforts are inconclusive; if you succeed, the con man (we’ll assume he lies) gets an Acting+5 roll. If he succeeds by more than you, then he appeared to be telling the truth; otherwise, he appeared to be lying. You get a +3 because of the lie detection equipment; he gets a +5 because he had time to craft his story. It would be appropriate to make the quality and quantity of lies caught dependent on your margin of successful in the contest.

Example 2: Without Lie Detection Equipment

At TL5 you ask a working women in a saloon her age and want to know if she’s telling you the truth. You have Detect Lies skill at 12; she does not have Acting skill. This is a contest of your Detect Lies-5 vs her IQ-5. You take full reduced-time penalties in a situation like this. After about of half hour of conversation and observation, you could ask again (at a -2 penalty this time, for a repeated attempt). Indeed, it is difficult to know with certainty when you are being lied to by a stranger in a social situation.

See Also

2d Damage optional | Combat Maneuvers | Interrogation | Meditation | Stealth | Tactics

STA main page