Summary: Should Lie Detection Be Admissible In Court
Should Lie Detection be Admissible in Court?
A Review of Literature
Abstract
Typical deceptive behavior does not exist and there are no perfect methods for deception using Behavioural or content analysis indicators. This report aims at critically evaluating psychological research on Lie Detection procedures. The report focuses on Behavioural indicators of deception with explicit reference to Ekman’s Emotion Theory (1992) and the common verbal and non-verbal cues to deception. The report goes on to describe Content Analysis techniques with direct reference to Criterion-Based Assessment (CBA) and Statement Validity Analysis (SVA) and their success rates as Lie Detection methods. The report outlines many …show more content…
studies that examine the success and failure rate of these verbal, non-verbal and Content Analysis techniques. Finally a critical review of the psychological research is made and it is concluded that from empirical research, the CBCA, SVA and Behavioural indicators of deception are not accurate enough to be admissible in court and that the current legislation should remain the same.
Should Lie Detection be Admissable in Court?
Unlike Pinocchio and his growing nose, liars do not seem to show any indicative signs of deception. It is hardly surprising that deception is difficult to detect, the intention of lies is to mislead after all. According to Virj (2000) the definition of Deception is “A successful deliberate attempt, without forewarning to create in another a belief which the communicator considers to be untrue” (p.6).
In critically examining the existing research, it is clear that there are in fact three different ways to out smart a liar. Firstly by observing their verbal and non-verbal behavior, secondly by analyzing the content of what they are saying and thirdly by examining their physiological responses. All of these methods are currently inadmissible in court, however due to the current revision in this ruling which is still awaiting decision, this report aims to outline why the first two methods i.e observing their verbal and nonverbal behavior and analyzing the content of what they are saying are in fact not effective enough to be admissible in court.
An infallible lie detection strategy would most certainly solve much of the criminal justice systems and psychologists’ problems in trying to identify deception within criminals. However at this point in time this is impossibility. This report will aim at outlining some effective approaches of differentiating truth from deception. It is clear that psychological research has provided huge insight into the area of lie detection and deception and have identified some extremely effective methods to aid the process of detecting lies within criminals, however these methods are not 100% accurate but may aid in the investigating process.
It is a known phenomenon that even the most professional of groups, including psychologists and police officers, are no better at determining the credibility of an individual than an average member of the public (Ekman, 1992, 1996). Garrido and Masip (1999) examined police officers and their ability to detect liars, results indicated that experienced police officers are no better than new recruits or the general public at detecting lies and that confidence about their ability to detect lies has no correlation to their actual lie detecting ability.
Behavioural Indicators of Deception: Some Verbal and Non-Verbal cues to Lying
There is no concrete way of determining the difference between truth and deception, however in light of new research this notion may be starting to change. So why are we having such trouble in detecting liars? Again there is no definite answer to this question however it could be because we are mistaken in our ideas of the cues of deception. Cues of deception will be discussed thoroughly in this report. Firstly, Behavioural indicators of deception will be discussed, this area has been heavily researched by psychologists. In recent research, it has been concluded that some Behavioural indicators of deception are more likely to occur during lying than others however this is dependent on emotion, content complexity and attempted behavioural control. All of these three aspects will be discussed.
According to Paul Ekman’s emotional approach, lying can occur as a result of different emotions.
Ekman (1992) outlines the problems associated with detecting lies. These problems include, the complex nature of the task of monitoring a liar’s behavior. It is extremely difficult to keep track of all aspects of a liar’s behavior, i.e their speech, facial expressions, voice expression, and all bodily movements and as a consequence, lie detectors may overlook some critical cues to deception (Ekman 1992). Also the indicators of emotion can be very difficult to interpret, as emotions are inaccurate indicators of deceit (Ekman, 1992). Ekman also argues that deception can result in differing emotions and the strength of the emotion is dependent on the personality of the liar and the context and circumstances of the lie. These emotions may in turn influence a liar’s non-verbal behavior and liars may attempt to control their behaviours in order to avoid getting caught. This may lead to a liar over controlling themselves and thus making their behavior look rehearsed, rigid and their speech too smooth, thus making non verbal behavior much more difficult to control than verbal …show more content…
behavior.
In a meta analyses conducted by Sporer & Schwandt (2006;2007), these researchers were able to identify some behavioural indicators of deception, particularly verbal and non verbal cues. Verbal cues include a higher pitch of voice, increased response latency, increased errors in speech and shorter lengths of descriptions (Sporer & Schwandt, 2006;2007). Non-verbal cues include decreased nodding, decreased foot and leg movements and decreased hand movements (Sporer & Schwandt, 2006;2007). These verbal and non verbal indicators are almost a summarized version of Ekman’s (1992) 38 item lying checklist conveying what he calls ‘leakages’ which are clues to detect deception.
Some of Ekman’s (1992) ‘Leakages’ include pauses and speech errors, which suggest lack of rehearsal of the story or being unprepared for interrogation resulting in strong negative fear emotions. Raised pitch voice and louder speech is also another indicator, which relates to a fear or anger response in the liar. Frequent swallowing along with faster breathing, sweating, increased blinking, whitening of the face and pupil dilation are all signs of emotion, however the lie detector must be careful when interpreting these physiological responses as they are an indicator of emotion, however it is not possible to detect which sort of emotion (Ekman 1992).
Ekman (1992) also examined clues that facial expressions can reveal about the emotion displayed being false. Ekman (1992) revealed that is it difficult to control facial communication and it can portray a liar’s true emotion to a trained observer. Micro-expressions are fleeting facial expressions which are unrelated to the expressed emotion are also another indicator of deception. Ekman identified six clues to do with facial expressions. The first being Asymmetrical face expressions, whereby each side of the face conveys a different emotion, which can be an indicator to falsehood (Ekman 1992). Another sign of falseness is the onset of the emotion conveyed should no be too abrupt and should be in accordance with the verbal account. Ekman also revealed that negative emotions, which do not accompany physiological responses such as sweating and breathing change, are most likely to be false. Ekman (1992) states that happiness should involve eye muscles, and if it doesn 't then the statement is likely to be false. Lastly, fear and sadness involve forehead expression and movement of the eyebrows, if this aspect if not present then deception is most likely occurring.
Content Indicators of Deception
The verbal and non-verbal indicators of deception have been examined, now content indicators of deception will be explored.
Content indicators of deception involve examining the content of speech in order to ascertain whether deception is taking place. By examining the language and associated verbal processes, some clues about detecting deception could be revealed. The Statement Validity Assessment (SVA) was developed in Germany to determine the credibility of certain content. Undeutsch (1992) was one of the pioneering psychologists and advocate of the Statement Validity Analysis (SVA).
SVA is accepted in a number of European legal systems, however not in UK courts. Opinion about SVA is divided in the USA but has still been used in the courtroom in the US.
SVA consists of two major components, including Criterion Based Content Analysis (CBCA) and the Validity Checklist. Usually, a semi-structured interview is conducted in order to obtain the content to be assessed. The content analysis relies heavily on the “Undeutsch hypothesis” which argues that a statement that comes solely fro memory of an actual experience is extremely different in content and quality from a statement that is fictitious and untruthful (Undeutsch, 1987). The actual process of analyzing content involves trained evaluators to judge the presence of absence or 19 criteria. The presence of each criterion strengthens the hypothesis that the account is based on genuine experience,
however the absence of a criterion does not necessarily mean the statement is false (Vrij, 2005).
The nineteen CBCA Criteria are broken down into four categories, General Characteristics, Specific Contents, Motivation-Related Content, and Offence Specific Elements. The General Characteristics of CBCA criteria include logical structure, unstructured production and quantity of details. The Specific Contents criteria includes; contextual embedding, descriptions of interactions, reproductions of conversation, unexpected complications during incident, unusual details, superfluous details, accurately reported details misunderstood, related external associations, accounts of subjective mental state and attribution of perpetrators mental state. Motivation Related Content criteria include spontaneous corrections, admitting lack of memory, raising doubts in testimony, self-deprecation and pardoning the perpetrator. Offence Specific elements include details characteristic of the offence.
The last stage of the SVA is the validity checklist. This involves the psychological assessment of victim and their possible motivations for giving a deceptive statement. Characteristics such as age, verbal skills and social skills of the participants are taken into consideration.
Success of Behavioural Indicators of Deception and Content Analysis Techniques
There has been much evidence to suggest the accuracy of examining behavioral indicators of deception and their correlation to lie detection. DePaulo et al. (2003) examined 159 verbal and nonverbal cues to deception and found evidence for the following 5 cues in deceptive statements, liars are less forthcoming, liars tell less compelling tales, liars are less positive and pleasant, liars are more tense and lies include less ordinary imperfections and more unusual details.
Porter and Yuille (1996) looked at verbal indicators of deception within interrogation settings. SVA along with two other methods of lie detection were used. Participants gave accounts that were either truthful or fictitious. Of the three methods, SVA was seen as most effective for determining truthful stories. Particularly apparent in truthful stories was the quantity of details, coherence/logical structure and lack of memory.
Vrij (2005) also provides support for SVA, he reviewed 37 experimental and field studies on the subject of CBCA. He found that in experimental studies, it was easier to establish the truthfulness of a statement because the consequences weren’t as threatening than real-life situations. He revealed that in 80% of the studies, truth tellers included more details, particularly criterion three. Vrij (2005) also revealed that in 69% of studies, truth tellers included much more contextual embedding and reproductions of conversation, i.e criteria four and six. Vrij (2005) also discovered that cognitive criteria (1-13) received more support than motivational criteria (14-18) and in 92% of experimental studies; truth tellers received a higher CBCA score than liars. Vrij (2005) reported that for experimental studies, overall accuracy was 55%-90%, however he argues heavily that CBCA is a truth verifying method not a lie detection technique.
Although there has been much success of the SVA method, there are also some concerns, which should not be ignored. Currently, the SVA has no formal decision rules or cut off points for truth or deception and according to Sporer (2004) some criteria should be given different weightings according to importance. It is also argued that different types of lies from subtle to outright may yield different levels/kinds of characteristics. SVA assessments are also extremely subjective and inter-rater reliability can be low, even after extensive training, and according to Akehurst et al., (2004) CBCA assessments of written statements are time consuming and even training may not improve accuracy.
In studies of accuracy rates of professional lie catchers it was found that on average across 9 mostly lab studies, by analyzing non-verbal behavior there was a 55% accuracy of detecting the truth across the studies. There was also a 55% chance of detecting a lie, found across those 9 studies examining non-verbal behavior alone. The accuracy of CBCA was also examined across 13 lab studies and it was found that professional lie catchers were able to detect the truth 76% of the time and detect deception 68% of the time. Both these methods of lie detection, are higher than the chance rate of 50%, however there has been recent evidence to suggest that using a combination of both methods result in increased accuracy.
Should verbal, non-verbal and content analysis techniques be admissible in court?
Although there has been proven success for verbal, non-verbal and content analysis, there has also been many studies proving these methods ineffective and are accompanied by many problems. Studies have shown that the CBCA score alone is not sufficient enough to determine whether deception is present, and the examiner must take into consideration external influences that could of affected the results such as leading questions by the interviewer and even the cognitive abilities of the witness. After all the CBCA is not a standardized test, so results need to be carefully interpreted.
There are many issues that have arisen as a result of the SVA, regarding the effectiveness of individual criteria and the effectiveness of the validity checklist. There still remains a concerning difference between laboratory and field studies, with laboratory studies yielding much more accurate results compared to field studies. Detection rates and false-positives are also an issue for the SVA, and SVA was specifically designed to measure children, so therefore how accurate can this test be for adults.
There are also many issues associated with CBCA, whereby not all statements are equally effective e.g a statement by a young child with not as much details will in turn have a lower score than that of an older child or adult. The problem of the criteria not being created equal is also an issue of concern, with beliefs that criteria 1 and 2 should be more heavily weighted as they are the most effective criteria for distinguishing truth tellers.
The Validity Checklist also presents problems in accuracy. The validity checklists are unable to determine whether a child is being externally coached by an adult and is becoming susceptible to suggestion, therefore there are difficulties in measurement. The validity checklist is highly subjective and is a more informal version of the CBCA, thus it is much harder to study and interpret.
The Daubert Standard (1993) is a set of standards in the US that consists of five criteria that must be met in order to be admissible in court. These five criteria include questions such as; is the scientific hypothesis testable? Has the proposition been tested? Is there a known error rate? Has the hypothesis and/or technique been subjected to peer review and publication? And is the theory upon which the hypothesis and/or technique based generally accepted in the appropriate scientific community? The error rate for CBCA judgments made in laboratory research is nearly 30% for both truths and lies, this is an extremely high rate.
Conclusion
Although the SVA is accepted in some European legal systems, it is in my professional opinion that while results are consistent with the Undeautsch Hypothesis and there have been some studies to prove the success of Behavioural Indicators of Deception. CBCA, SVA and verbal and non-verbal Behavioural indicators of deception should not be admissible in court as there is too much evidence outlining the problems and concerns with these procedures that have been scientifically proven, the error rate is too high and the SVA does not meet the requirements of the Daubert Standard.
However in light of empirical evidence, perhaps CBCA and SVA would be effective in the initial stages of investigation to discern deceit and deception and results can then be used to guide police investigations, however it is clearly evident that from the psychological research conveyed in this report conveying both the advantages and disadvantages, the disadvantages and problems with these types of analysis far outweigh the success rates. Thus, lie detection procedures should not be admissible in court and the legal system should remain unchanged.
References
DePaulo, B. M., Lindsay, J. J., Malone, B. E., Muhlenbruck, L., Charlton, K., & Cooper, H. (2003). Cues to deception. Psychological Bulletin, 129, 74-118.
Ekman, P. (1992). Telling Lies: Clues to deceit in the marketplace, marriage, and politice (2nd ed.). New York: Norton.
Ekman, P. (1996) Why don’t we catch liars? Social Research, 63, 801-817.
Garrido, E, & Massip, J. (1999(. How good are police officers at spotting lies? Forensic Update, 50.
Masip, J., & Garrido, E. (1999). The detection of deception with the reality monitoring approach: A review of the empirical evidence. Psychology, Crime, & Law.
Porter, S., & Yuille, J. C. (1996). The language of deceit: an investigation of the verbal clues in the interrogation context. Law and Human Behavior, 20, 443.
Sporer, S., & Schwandt, B. (2006). Paraverbal indicators of deception: A meta-analytic synthesis. Applied Cognitive Psychology, 20, 421–466.
Sporer, S. L., & Schwandt, B. (2007). Moderators of nonverbal indicators of deception: A meta-analytic synthesis. Psychology, Public Policy, and Law, 13, 1-34.
Vrij, A. (2000). Detecting lies and deceit. The psychology of lying and the implications for professional practice. Chichester: Wiley
Vrij, A. (2005). Criteria-Based Content Analysis: A qualitative review of the first 37 studies. Psychology, Public Policy, and Law, 11, 3-41.
A Review of Literature
Abstract
Typical deceptive behavior does not exist and there are no perfect methods for deception using Behavioural or content analysis indicators. This report aims at critically evaluating psychological research on Lie Detection procedures. The report focuses on Behavioural indicators of deception with explicit reference to Ekman’s Emotion Theory (1992) and the common verbal and non-verbal cues to deception. The report goes on to describe Content Analysis techniques with direct reference to Criterion-Based Assessment (CBA) and Statement Validity Analysis (SVA) and their success rates as Lie Detection methods. The report outlines many …show more content…
studies that examine the success and failure rate of these verbal, non-verbal and Content Analysis techniques. Finally a critical review of the psychological research is made and it is concluded that from empirical research, the CBCA, SVA and Behavioural indicators of deception are not accurate enough to be admissible in court and that the current legislation should remain the same.
Should Lie Detection be Admissable in Court?
Unlike Pinocchio and his growing nose, liars do not seem to show any indicative signs of deception. It is hardly surprising that deception is difficult to detect, the intention of lies is to mislead after all. According to Virj (2000) the definition of Deception is “A successful deliberate attempt, without forewarning to create in another a belief which the communicator considers to be untrue” (p.6).
In critically examining the existing research, it is clear that there are in fact three different ways to out smart a liar. Firstly by observing their verbal and non-verbal behavior, secondly by analyzing the content of what they are saying and thirdly by examining their physiological responses. All of these methods are currently inadmissible in court, however due to the current revision in this ruling which is still awaiting decision, this report aims to outline why the first two methods i.e observing their verbal and nonverbal behavior and analyzing the content of what they are saying are in fact not effective enough to be admissible in court.
An infallible lie detection strategy would most certainly solve much of the criminal justice systems and psychologists’ problems in trying to identify deception within criminals. However at this point in time this is impossibility. This report will aim at outlining some effective approaches of differentiating truth from deception. It is clear that psychological research has provided huge insight into the area of lie detection and deception and have identified some extremely effective methods to aid the process of detecting lies within criminals, however these methods are not 100% accurate but may aid in the investigating process.
It is a known phenomenon that even the most professional of groups, including psychologists and police officers, are no better at determining the credibility of an individual than an average member of the public (Ekman, 1992, 1996). Garrido and Masip (1999) examined police officers and their ability to detect liars, results indicated that experienced police officers are no better than new recruits or the general public at detecting lies and that confidence about their ability to detect lies has no correlation to their actual lie detecting ability.
Behavioural Indicators of Deception: Some Verbal and Non-Verbal cues to Lying
There is no concrete way of determining the difference between truth and deception, however in light of new research this notion may be starting to change. So why are we having such trouble in detecting liars? Again there is no definite answer to this question however it could be because we are mistaken in our ideas of the cues of deception. Cues of deception will be discussed thoroughly in this report. Firstly, Behavioural indicators of deception will be discussed, this area has been heavily researched by psychologists. In recent research, it has been concluded that some Behavioural indicators of deception are more likely to occur during lying than others however this is dependent on emotion, content complexity and attempted behavioural control. All of these three aspects will be discussed.
According to Paul Ekman’s emotional approach, lying can occur as a result of different emotions.
Ekman (1992) outlines the problems associated with detecting lies. These problems include, the complex nature of the task of monitoring a liar’s behavior. It is extremely difficult to keep track of all aspects of a liar’s behavior, i.e their speech, facial expressions, voice expression, and all bodily movements and as a consequence, lie detectors may overlook some critical cues to deception (Ekman 1992). Also the indicators of emotion can be very difficult to interpret, as emotions are inaccurate indicators of deceit (Ekman, 1992). Ekman also argues that deception can result in differing emotions and the strength of the emotion is dependent on the personality of the liar and the context and circumstances of the lie. These emotions may in turn influence a liar’s non-verbal behavior and liars may attempt to control their behaviours in order to avoid getting caught. This may lead to a liar over controlling themselves and thus making their behavior look rehearsed, rigid and their speech too smooth, thus making non verbal behavior much more difficult to control than verbal …show more content…
behavior.
In a meta analyses conducted by Sporer & Schwandt (2006;2007), these researchers were able to identify some behavioural indicators of deception, particularly verbal and non verbal cues. Verbal cues include a higher pitch of voice, increased response latency, increased errors in speech and shorter lengths of descriptions (Sporer & Schwandt, 2006;2007). Non-verbal cues include decreased nodding, decreased foot and leg movements and decreased hand movements (Sporer & Schwandt, 2006;2007). These verbal and non verbal indicators are almost a summarized version of Ekman’s (1992) 38 item lying checklist conveying what he calls ‘leakages’ which are clues to detect deception.
Some of Ekman’s (1992) ‘Leakages’ include pauses and speech errors, which suggest lack of rehearsal of the story or being unprepared for interrogation resulting in strong negative fear emotions. Raised pitch voice and louder speech is also another indicator, which relates to a fear or anger response in the liar. Frequent swallowing along with faster breathing, sweating, increased blinking, whitening of the face and pupil dilation are all signs of emotion, however the lie detector must be careful when interpreting these physiological responses as they are an indicator of emotion, however it is not possible to detect which sort of emotion (Ekman 1992).
Ekman (1992) also examined clues that facial expressions can reveal about the emotion displayed being false. Ekman (1992) revealed that is it difficult to control facial communication and it can portray a liar’s true emotion to a trained observer. Micro-expressions are fleeting facial expressions which are unrelated to the expressed emotion are also another indicator of deception. Ekman identified six clues to do with facial expressions. The first being Asymmetrical face expressions, whereby each side of the face conveys a different emotion, which can be an indicator to falsehood (Ekman 1992). Another sign of falseness is the onset of the emotion conveyed should no be too abrupt and should be in accordance with the verbal account. Ekman also revealed that negative emotions, which do not accompany physiological responses such as sweating and breathing change, are most likely to be false. Ekman (1992) states that happiness should involve eye muscles, and if it doesn 't then the statement is likely to be false. Lastly, fear and sadness involve forehead expression and movement of the eyebrows, if this aspect if not present then deception is most likely occurring.
Content Indicators of Deception
The verbal and non-verbal indicators of deception have been examined, now content indicators of deception will be explored.
Content indicators of deception involve examining the content of speech in order to ascertain whether deception is taking place. By examining the language and associated verbal processes, some clues about detecting deception could be revealed. The Statement Validity Assessment (SVA) was developed in Germany to determine the credibility of certain content. Undeutsch (1992) was one of the pioneering psychologists and advocate of the Statement Validity Analysis (SVA).
SVA is accepted in a number of European legal systems, however not in UK courts. Opinion about SVA is divided in the USA but has still been used in the courtroom in the US.
SVA consists of two major components, including Criterion Based Content Analysis (CBCA) and the Validity Checklist. Usually, a semi-structured interview is conducted in order to obtain the content to be assessed. The content analysis relies heavily on the “Undeutsch hypothesis” which argues that a statement that comes solely fro memory of an actual experience is extremely different in content and quality from a statement that is fictitious and untruthful (Undeutsch, 1987). The actual process of analyzing content involves trained evaluators to judge the presence of absence or 19 criteria. The presence of each criterion strengthens the hypothesis that the account is based on genuine experience,
however the absence of a criterion does not necessarily mean the statement is false (Vrij, 2005).
The nineteen CBCA Criteria are broken down into four categories, General Characteristics, Specific Contents, Motivation-Related Content, and Offence Specific Elements. The General Characteristics of CBCA criteria include logical structure, unstructured production and quantity of details. The Specific Contents criteria includes; contextual embedding, descriptions of interactions, reproductions of conversation, unexpected complications during incident, unusual details, superfluous details, accurately reported details misunderstood, related external associations, accounts of subjective mental state and attribution of perpetrators mental state. Motivation Related Content criteria include spontaneous corrections, admitting lack of memory, raising doubts in testimony, self-deprecation and pardoning the perpetrator. Offence Specific elements include details characteristic of the offence.
The last stage of the SVA is the validity checklist. This involves the psychological assessment of victim and their possible motivations for giving a deceptive statement. Characteristics such as age, verbal skills and social skills of the participants are taken into consideration.
Success of Behavioural Indicators of Deception and Content Analysis Techniques
There has been much evidence to suggest the accuracy of examining behavioral indicators of deception and their correlation to lie detection. DePaulo et al. (2003) examined 159 verbal and nonverbal cues to deception and found evidence for the following 5 cues in deceptive statements, liars are less forthcoming, liars tell less compelling tales, liars are less positive and pleasant, liars are more tense and lies include less ordinary imperfections and more unusual details.
Porter and Yuille (1996) looked at verbal indicators of deception within interrogation settings. SVA along with two other methods of lie detection were used. Participants gave accounts that were either truthful or fictitious. Of the three methods, SVA was seen as most effective for determining truthful stories. Particularly apparent in truthful stories was the quantity of details, coherence/logical structure and lack of memory.
Vrij (2005) also provides support for SVA, he reviewed 37 experimental and field studies on the subject of CBCA. He found that in experimental studies, it was easier to establish the truthfulness of a statement because the consequences weren’t as threatening than real-life situations. He revealed that in 80% of the studies, truth tellers included more details, particularly criterion three. Vrij (2005) also revealed that in 69% of studies, truth tellers included much more contextual embedding and reproductions of conversation, i.e criteria four and six. Vrij (2005) also discovered that cognitive criteria (1-13) received more support than motivational criteria (14-18) and in 92% of experimental studies; truth tellers received a higher CBCA score than liars. Vrij (2005) reported that for experimental studies, overall accuracy was 55%-90%, however he argues heavily that CBCA is a truth verifying method not a lie detection technique.
Although there has been much success of the SVA method, there are also some concerns, which should not be ignored. Currently, the SVA has no formal decision rules or cut off points for truth or deception and according to Sporer (2004) some criteria should be given different weightings according to importance. It is also argued that different types of lies from subtle to outright may yield different levels/kinds of characteristics. SVA assessments are also extremely subjective and inter-rater reliability can be low, even after extensive training, and according to Akehurst et al., (2004) CBCA assessments of written statements are time consuming and even training may not improve accuracy.
In studies of accuracy rates of professional lie catchers it was found that on average across 9 mostly lab studies, by analyzing non-verbal behavior there was a 55% accuracy of detecting the truth across the studies. There was also a 55% chance of detecting a lie, found across those 9 studies examining non-verbal behavior alone. The accuracy of CBCA was also examined across 13 lab studies and it was found that professional lie catchers were able to detect the truth 76% of the time and detect deception 68% of the time. Both these methods of lie detection, are higher than the chance rate of 50%, however there has been recent evidence to suggest that using a combination of both methods result in increased accuracy.
Should verbal, non-verbal and content analysis techniques be admissible in court?
Although there has been proven success for verbal, non-verbal and content analysis, there has also been many studies proving these methods ineffective and are accompanied by many problems. Studies have shown that the CBCA score alone is not sufficient enough to determine whether deception is present, and the examiner must take into consideration external influences that could of affected the results such as leading questions by the interviewer and even the cognitive abilities of the witness. After all the CBCA is not a standardized test, so results need to be carefully interpreted.
There are many issues that have arisen as a result of the SVA, regarding the effectiveness of individual criteria and the effectiveness of the validity checklist. There still remains a concerning difference between laboratory and field studies, with laboratory studies yielding much more accurate results compared to field studies. Detection rates and false-positives are also an issue for the SVA, and SVA was specifically designed to measure children, so therefore how accurate can this test be for adults.
There are also many issues associated with CBCA, whereby not all statements are equally effective e.g a statement by a young child with not as much details will in turn have a lower score than that of an older child or adult. The problem of the criteria not being created equal is also an issue of concern, with beliefs that criteria 1 and 2 should be more heavily weighted as they are the most effective criteria for distinguishing truth tellers.
The Validity Checklist also presents problems in accuracy. The validity checklists are unable to determine whether a child is being externally coached by an adult and is becoming susceptible to suggestion, therefore there are difficulties in measurement. The validity checklist is highly subjective and is a more informal version of the CBCA, thus it is much harder to study and interpret.
The Daubert Standard (1993) is a set of standards in the US that consists of five criteria that must be met in order to be admissible in court. These five criteria include questions such as; is the scientific hypothesis testable? Has the proposition been tested? Is there a known error rate? Has the hypothesis and/or technique been subjected to peer review and publication? And is the theory upon which the hypothesis and/or technique based generally accepted in the appropriate scientific community? The error rate for CBCA judgments made in laboratory research is nearly 30% for both truths and lies, this is an extremely high rate.
Conclusion
Although the SVA is accepted in some European legal systems, it is in my professional opinion that while results are consistent with the Undeautsch Hypothesis and there have been some studies to prove the success of Behavioural Indicators of Deception. CBCA, SVA and verbal and non-verbal Behavioural indicators of deception should not be admissible in court as there is too much evidence outlining the problems and concerns with these procedures that have been scientifically proven, the error rate is too high and the SVA does not meet the requirements of the Daubert Standard.
However in light of empirical evidence, perhaps CBCA and SVA would be effective in the initial stages of investigation to discern deceit and deception and results can then be used to guide police investigations, however it is clearly evident that from the psychological research conveyed in this report conveying both the advantages and disadvantages, the disadvantages and problems with these types of analysis far outweigh the success rates. Thus, lie detection procedures should not be admissible in court and the legal system should remain unchanged.
References
DePaulo, B. M., Lindsay, J. J., Malone, B. E., Muhlenbruck, L., Charlton, K., & Cooper, H. (2003). Cues to deception. Psychological Bulletin, 129, 74-118.
Ekman, P. (1992). Telling Lies: Clues to deceit in the marketplace, marriage, and politice (2nd ed.). New York: Norton.
Ekman, P. (1996) Why don’t we catch liars? Social Research, 63, 801-817.
Garrido, E, & Massip, J. (1999(. How good are police officers at spotting lies? Forensic Update, 50.
Masip, J., & Garrido, E. (1999). The detection of deception with the reality monitoring approach: A review of the empirical evidence. Psychology, Crime, & Law.
Porter, S., & Yuille, J. C. (1996). The language of deceit: an investigation of the verbal clues in the interrogation context. Law and Human Behavior, 20, 443.
Sporer, S., & Schwandt, B. (2006). Paraverbal indicators of deception: A meta-analytic synthesis. Applied Cognitive Psychology, 20, 421–466.
Sporer, S. L., & Schwandt, B. (2007). Moderators of nonverbal indicators of deception: A meta-analytic synthesis. Psychology, Public Policy, and Law, 13, 1-34.
Vrij, A. (2000). Detecting lies and deceit. The psychology of lying and the implications for professional practice. Chichester: Wiley
Vrij, A. (2005). Criteria-Based Content Analysis: A qualitative review of the first 37 studies. Psychology, Public Policy, and Law, 11, 3-41.