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Detecting Deception - 2011
Transcript of Detecting Deception - 2011
Contact Body Language How does it work? Psychological Literature Lying during a police interview Detecting Liars Through Eye Contact Question Detecting Deception Presented by
Melissa Phelan What is deception? Eye Contact Body Language Polygraph Test Micro-Expressions TRUTH Detecting Deception Assigned Question There are a number of ways in which deception can be detected. Your task is to discuss the ability of humans to accurately detect deception, making reference to empirical research findings. Conclusion "I didn't do it!" "It wasn't me!" "I wasn't there!" "That's not mine!" "I'm 21!" "I'm naturally blonde!" "I own that!" "I didn't touch it!" "I found it!" "I didn't know it was illegal!" "They made me do it!" "He said he was single!" "I was drunk!" "I've only had 2 drinks!" "I saw the girl with brown hair do it..." "The car was a red sedan!" "Of course I have my licence!" "I'm single!" "It was that guy!" "It was on sale!" Findings:
Some suspects looked away more when lying and some increased their degree of eye contact.
Liars blinked less frequently and paused for a longer period of time when speaking.
65% success rate in telling when someone was lying compared to when someone was telling the truth.
This study highlights that detecting lies through individuals eye contact patterns is difficult as different people perform a diverse range of eye contact patterns in a variety of situations. Eye Contact Patterns Study Conclusions Findings:
These detectives performed poorly in identifying liars, earning an overall accuracy rate of 49 % (Vridj, 2008).
Vridj (2008) highlights in his research that eye contact is not related to deception at all. “How can you tell when people are lying?”
Scientists asked 2000 people from nearly 60 countries this exact question. The number one answer was the same. Liars avert their gaze. Video Activity The Triune Brain Theory The Reptilian Complex The Limbic System The Neocortex/Cerebral Cortex (MacLean, 1952) The theory states there are 3 components of the brain that act together. Adults are no better at detecting deception in children as they are adults, and it is more difficult to detect deception in girls than boys. Conclusion Gender The time they have to prepare and rehearse the lie
Influencing Factors Gulp
Stroke facial hair
Rub back of neck
Touch their face more
Button up coat (defense)
Collar tug (“hot under the collar”)
Male Female Decrease in smiling
Crossing arms or legs
Clasping hands in lap
Tug on the earlobe, putting hand to face
Rubbing nose or back of neck
Shifting postures in their chair
Half-shoulder shrug indicates a lack of confidence in what they are saying
Placing distance between themselves and the interviewer by leaning back or turning their body away from the interviewer – if one’s feet are pointed away from a person, they are feeling uncomfortable and their feet indicate the direction they would like to go Blocking Behaviours Interesting Facts Without being familiar with a person’s normal behaviour, it is difficult to detect deception through body language. For this reason, police officers are generally no better at detecting deception than the general population, and when they do, it is usually by chance. The kind of lie The motivations for the lie How many times they have repeated the lie The knowledge of the persons normal behaviour The length of the interview Whether they are a compulsive liar Involuntary life support functions and survival impulses. Uses little or no conscious thought. Associates events with emotions and is responsible for memory and recall. Responsible for advanced cognition, speech and voluntary actions. When faced with threat, such as interrogating questions, the stress response is stimulated, with physiological effects to ensure survival. Stress chemicals activate the limbic system.
The most efficient way for the body to get rid of stress chemicals is to move. Moving relieves tension and attempts to calm and comfort the body – these movements are known as nervous habits, or non verbal cues.
Essentially, the reptilian complex releases the stress chemicals, which activates the limbic system and nervous system, and the neocortex attempts to suppress the stress chemicals and movements, while at the same time formulating lies.When the neocortex fails to suppress movements, it is called leakage – “while the neocortex may lie, the body cannot” (Navarro, 2008) 57% Behavioural Analysis Interview Tug at skirt
Close gap at neck of shirt if unbuttoned
Play with top button of shirt, or necklace
Fanning themselves with hand when overheated
Place fingers at the base of their throat – speed of which hand raises to throat directly related to degree of stress (“Stress Meter”, Navarro, 2008)
Vrij, Mann and Fisher (2006) Limitations Deception can be defined as causing someone to believe somthing that is not true. Question Time Tell us what you have learned!
Anything out of the ordinary?
Did you think differently before? References Learning Outcomes Reliability and Empirical Evidence Micro Expressions Micro:
Small or denoting factor of one millionth.
Aspect of face, intonation of voice esp. as indicating emotion. Definition Minute displays of true and actual thought processes.
They can last anywhere between 0.667-4.0 seconds.
What are they? Not all of the muscles of the face are available for voluntary movement.
Particular muscles of the face contract in response to an emotion.
These movements are involuntary. This helped define the idea that a true smile, denoted within the field as a Duchenne Smile, of ‘frank joy’ can not be faked. Duchenne Smile The set of muscles not controlled by the motor cortex of the human brain (orbicularis oculi) could only be stimulated by emotions. The following photographs are from the original study but are taken from a later review (Ekman, Davidson & Friesen, 1990). Previously undiscovered facts Duchenne de Boulogne, Mecanisme de la Physionomie Humain (1862) were commonly accepted as the positive emotions that were expressed through the involuntary contraction of the orbicularis oculi. Happiness, Enjoyment & Satisfaction Different emotions that the Duchenne smile represents.... Often interpreted incorrectly
In relation to criminal justice system, are not admissible as evidence. Ekman on Darwin Guilty Knowledge Test Controlled Question Test Based upon questions that only the investigator or interviewer and the guilty perpetrator would know. These questions are asked sequentially whilst the physiological signals are recorded. Several answers are provided to the suspect, both correct and plausible but incorrect answers. Innocent suspect: similar responses
Guilty suspects: the correct answer should elicit an enhanced physiological response.
Several of these questions should be posed to the suspect and a stronger response to correct information to the crime should be indicated. The Guilty Knowledge/Concealed Information Test. For Example Was the victim killed with a (a) gun, (b) bat, (c) ice pick, (d) knife? Limitations The possibility of a false-positive outcome - Based on two factors; (a) the number of questions and answers provided to the suspect and (b) probability.
Likelihood of the guilty suspect being the only suspect/person to know intimate details of the crime.
Likelihood of avoiding media influence on information relating to a crime.
Although, the positive of this is that the probability of the results being incorrect can be tested and introduced into court proceedings. Conclusion Elaad (1998) reviewed 15 mock crime studies and found average detection rates of 81% for guilty examinees and 96% for innocent.
Similarly, Ben-Shakhar and Furedy (1990) reviewed 10 mock crime studies and found average detection rates of 84% guilty and 94% innocent.
The results of this type of questioning are more promising however the technique is still not as widely used. This is mostly due to the fact that the ability to accurately test the technique is very limited.
A more recent study reviewed the very minimum standards and showed accuracy levels of 85% - 89%.
Polygraph tests can discriminate lying from truth telling at rates well above chance, though well below perfection.
Accuracy E Meijer and B Verschuere (2010) 74% to 89% for guilty examinees
59% - 83% for innocent examinees
a false-negative for 1% to 13%.
a false positive ratio from 10% to 23% Limitations The general assumption that a suspect will be more concerned about the controlled question.
There is little way of testing the true accuracy of this type of questioning as most studies are instructed to commit a ‘mock’ crime whilst the others are instructed to be innocent. Relevant ‘hot’ question
- eg. Did you stab your ex-wife Sarah
Irrelevant ‘cold’ question
- eg. Is your name John Smith?
- eg. In the first 20 years of your life did you ever seriously hurt someone? Polygraph tests can distinguish lying from truth telling at rates well above chance, though well below perfection.
The incorrect outcomes of polygraph test, in particular the controlled question test, are significantly due to the inability to distinguish between an innocents fear of false detection and a guilty persons fear of detection.
The available studies show a reasonable rate of deception detection however the ability of these studies to accurately duplicate a true investigation scenario are highly limited which in turn questions the validity of the results.
Ekman, Davidson and Friesen (1990) These can then indicate whether a person is smiling honestly and truly or using only the muscles they have control over. Micro expressions are not always present.
When they are present however they are a good measure of ‘leaking emotions’. In 2003, Ekman compared his own findings with those of Darwin in 1874, these were his findings: Original proposition that emotions have universal facial expressions was supported. The key to using facial expressions as a method of detecting deception is in the use of non-voluntary muscles. Respiration - recorded from belts around the chest and abdomen. Then a laptop computer is used to digitize and record physiological reactions to the relevant and control questions. There are two main types of question styles used when applying the polygraph test: The Controlled Question Test & The Guilty Knowledge Test Cardiovascular activity or blood pressure - tracked from a partially inflated blood pressure cuff placed around one arm. It measures: 3 Types of Questions Why? Stakes were much lower than in real life.
The liars knew what to expect and could prepare themselves for being deceptive.
Some questions were on a Likert scale and therefore did not require elaborate answers.
The liars had a chance to familiarise themselves with the story they were given to tell. Liars were less likely to shift in their seat or cross their arms or legs, than truth tellers.
Liars reportedly tried significantly harder to appear honest than the truth tellers Findings Charles Bond -“this is… the most prevalent stereotype of deception in the world” Findings:
Subjects who were told to provide false information gazed at the counsellor longer than subjects who provided the truth.
Someone who attempts to deceive someone increases eye contact rather than avoiding it.
This behaviour may aim to fulfil cultural expectations that eye contact indicates truthfulness Indicates that neither gaze aversion nor eye contact are effective indicators of deception (DePaulo et al., 2003).
“A lying suspect’s eyes will appear foggy, puzzled, probing, pleading (as though seeking pity), evasive or shifty, cold, hard, strained, or sneaky. A truthful person’s eyes will appear clear, bright, alert, warm, direct, easy, soft, and unprobing” (Inbau et al., 2001, p. 152).
Reading such criminal justice sources leads one to believe there are concrete techniques for detecting deception. Unfortunately, the psychological literature does not support this conclusion. Overall, detecting deception in field settings is difficult.
The majority of subjects, whether trained or untrained, experienced criminal justice system employees or college students, perform at levels insignificantly better than chance.
The notion that criminal justice employees can eyeball suspects and accurately determine when they lie is a myth (King & Dunn, 2009). The following deception detection techniques will be discussed in this presentation: Deceptive communication is a common feature of everyday life.
Due to the pervasive nature of deception in society, people are required, on a regular basis, to assess the credibility of information.
Therefore the detection of deception has fascinated humanity throughout history. DePaulo, B.M., Lindsay, J.J., Malone, B.E., Muhlenbruck, L., Charlton, K. & Cooper, H. (2003), “Cues to deception”, Psychological Bulletin, Vol. 129, pp. 74-118.
Ekman, P. (2003). Darwin, deception and facial expression. Annals of the New York Academy of Sciences, 1000, 205-221.
Ekman, P., Davidson R. J., & Friesen, W. V. (1990). The Duchenne Smile: Emotional expression and brain psychology II. Journal of Personality and Social Psychology, 58(2), 342-353.
Iacono, W. (2008). Understanding how polygraphs work and are used. Criminal Justice and Behaviour, (35)10, 1295-1308.
Iacono, W. G., & Lykken, D. T. (1997). The valitiy of the lie detector: Two surveys of scientific opinion. Journal of Appllied Psychology, 82(3), 426-433.
Kapardis, A. (2010). Psychology and law: A critical introduction. Melbourne, Australia: Cambridge University Press.
King, W., & Dunn, T. (2009). Detecting deception in field settings. Policing: An international Journal of Police Stratergies and Management, 33(2), 305-220.
Lock, C. (2004). Deception detection: psychologists try to learn how to spot a liar. Science News, 166(5), 72.
Meijer, E. H., Verschuere, B. (2010). The polygraph and the detection of deception. Journal of Foresnsic Psychology Practice, (10)4, 325-338.
Pozzato, L. (2010). Interpreting nonverbal communication for use in detecting deception. Forensic Examiner, 19(3).
Sitton, S. (1981). Detection of Deception From Clients' Eye Contact Patterns. Journal of Counesling Psychology, 28(3), 269.
Vridj, A. (2008). Detecting lies and deceipt: pitfalls and opportunities. West Sussex, England: John Wiley and Sons Ltd.
Vrij, A., & Mann, S. (2004). Detecting Deception: The benefit of looking at a combination of behavioural, auditory and speech content related cues in a systematic manner. Group Decision and Negotiation, 13. 61-79.
Vrij, A., Mann, S., & Fisher, R. (2006). An Empirical Test of the Behaviour Analysis Interview. Law and Human Behaviour, 30(3), 329-345. The person to ask the best question will receive a prize. Empirical evidence of the discussed methods of detecting decpetion suggest that at the moment there is no significantly accurate method to detect deception. Conclusions (Oxford Australian Intergrated School Dictionary & Thesaurus, 2009) Eye Contact - Eliza
Body Language - Melissa
Micro Expressions - Nick
Activity - Katelyn
Polygraph Tests - Greta Disgust Anger Sadness Contempt Suprise Fear Develops an understanding of deception detction methods.
Presents empirical research findings on detecting deception. Micro expressions are small involuntary movements that are uncontrollable by the human brain.
These movements give us an accurate measure of another persons intentions but are not always present.
The use of micro expressions as a method of detecting deception can be accurate however it is not admissable as evidence and so is only useful during interviews. Prezi created by Katelyn Murray