L13 Lie detection Flashcards
Define deception
• “A successful or unsuccessful deliberate attempt, without forewarning, to create in another a belief which the communicator considers to be untrue” (Vrij, 2000)
- Must be intentional deception
- Without forewarning (magicians aren’t liers because we expect to be deceived by them
- Depends on the perspective of the deceiver (child ate cookies in cookie jar. Then those in cupboard. Says mum I want more cookies. She says there are no more cookies. She is lying to the child because she BELIEVES there are more, but there are not.
- Involves two people, doesn’t include telling lies to ourselves
Types of Lies (DePaulo et al., 1996)
- Outright lies (guilty suspect says I didn’t do it)
- Exaggerations (facts are overstated or info is conveyed in a way that exceeds the truth. E.g. forensic suspect embellishes the remorse to get a lighter sentence.)
- Subtle lies (literal truths that are designed to mislead. E.g. concealing info, evading a question or omitting relevant details.)
Reasons to Lie
• 5 reasons (Vrij, 2000):
–To gain personal advantage (business man knows company is not doing well. Don’t tell your stockholders)
–To avoid punishment (Say I didn’t commit the crime to avoid conviction)
–To make a positive impression on others (say how great we are)
–To protect themselves from embarrassment/ disapproval (don’t admit to mistakes)
–For the sake of social relationships (e.g. the movie “the invention of lying”. If you don’t lie, you would have to say outright,” I hoped you would be better looking” on a blind date”
Self- Oriented vs others oriented. (saying you did it so your son won’t go to jail)
Frequency of Lying; Who Lies?
Children lie as soon as they have theory of mind, animals can lie (Koko the gorilla)
• American diary study: college students told 2 lies/day and community members told 1 lie/day. Most lies were self-serving (DePaulo, 1996)
• Frequency of lying depends on:
1. The personality and gender of the liar
2. The situation in which the lie is told
3. People to whom the lie is told
Which personality types and gender lies more?
– Extroverts lie more than introverts
– Frequency of lies similar between men and women
–Women tell more social lies
–When dating, women lie to improve physical appearance, men lie to exaggerate earning potential
How many people lie to jet a date or job?
– 90% lie to prospective date
– 83% lie to get a job
Who do people tell lies to?
- People to whom the lie is told:
– Lowest rate of lying with spouses
– Highest rate of lying with strangers
– College students lie frequently to their mothers (in almost half of their conversations)
Three ways to catch a liar
- Observe their verbal and nonverbal behaviour*
- Analyse the content of what they say*
- Examine their physiological responses (lie detector tests)
Some verbal and nonverbal cues are more likely to occur during deception than others, depending on:
- Emotion (paul ekman’s approach)
- Content complexity
- Attempted behavioural control
Paul Ekman’s emotional approach: Behavioural indicators of deceeption
- – Deception results in different emotions: guilt (we tend to overt our gaze when guilty) , fear, excitement (duping delight = getting excited about the prospect of telling a lie, Leads to arousal = increase in limb movements, increased speech fillers ums and ahs, increased speech errors, incomplete sentences, higher pitched voice.)
However, sometimes people telling the truth leads to high arousal (if you’re concerned someone will falsly believe you’re lying)
– Strength of emotion depends on personality of liar and circumstances of lie
– Emotions may influence a liar’s Nonverbal Behaviour (NVB)
– NVB during deception should show signs of stress compared to baseline of typical NVB
Why does Content complexity make lying can be difficult to do
• People engaged in cognitively complex tasks exhibit different nonverbal behaviors
Avoid contradicting evidence out there, remember evidence etc.
When we engage in complex tasks, we have more speech errors, pause more to think of the response, we neglect our body language, move our limbs less.
We avert our gaze to an emotionless point because we don’t want to get distracted by things.
In these ways content complexity can be a behavioural indicator of deception.
By creating highly difficult questions for people, you can distinguish between liars and truth tellers. E.g. “can you sketch out the area”. “tell things in reverse order” tell subject to look into your eyes
What is the impact and consequence of liars attempting to control their behaviour?
• When liars do this, they sometimes over-control themselves, resulting in rehearsed and rigid behaviour
• Nonverbal behaviour is more difficult to control than verbal behaviour, a lot of people do attempt to control it.
- There are more automatic links between words and behaviour
- We are more practiced at controlling behaviour
Behavioural Indicators of Deception: Verbal and Nonverbal Cues to Lying Meta-analyses by Sporer & Schwandt (2006; 2007)
• Verbal cues:
1. Higher pitch of voice
2. Increased response latency (takes us longer to respond)
3. Increased errors in speech (ums and ahs, mixing up sentences)
4. Shorter length of description
• Nonverbal Cues:
5. Decreased nodding (still and stoic)
6. Decreased foot and leg movements
7. Decreased hand movements
The literature is a bit mixed and this is quite hard to determine
• Microexpressions
A fleeting facial expression discordant with the expressed emotion and usually suppressed within 1/5 to 1/25 of a second
• It is difficult to control facial communication and it can betray a deceiver’s true emotion to a trained observer (Ekman, 1992)
• Inconsistent emotional leakage occurred in 100% of participants at least once. Negative emotions were more difficult to falsify than happiness (Porter & ten Brinke, 2008)
What is a Content Indicator of Deception
Statement Validity Assessment (SVA)
