ABSTRACT
Traditional polygraph techniques mostly rely on the changes of an individual's physiological indicators, such as electrodermal activity, heart rate, breath, eye movement and function of neural signals and other indicators. They are easily affected by individual physical conditions, counter-tests, external environment and other aspects, and it is difficult to conduct large-scale screening tests based on the traditional polygraph techniques. The application of keystroke dynamics to polygraph can overcome the shortcomings of the traditional polygraph techniques to a large extend, increase the reliability of polygraph results and promote the validity of legal evidence of polygraph results in forensic practice. This paper introduces keystroke dynamics and its application in deception research. Compared with the traditional polygraph techniques, keystroke dynamics can be used with a relatively wider application range, not only for deception research but also for identity identification, network screening and other large-scale tests. At the same time, the development direction of keystroke dynamics in the field of polygraph is prospected.
Subject(s)
Lie Detection , Reproducibility of Results , Forensic Medicine , DeceptionABSTRACT
Objective To investigate the application value of eye tracking in lie detection. Methods The 40 subjects were randomly divided into two groups. The pupil diameter, fixation duration, points of fixation and blink frequency of the subjects in the experimental group in observing target stimulation and non-target stimulation were recorded with eye tracker after they accomplished the mock crime. The eye movement parameters of subjects in the control group were directly collected. The differences in eye movement parameters of the experimental group and the control group in observing target stimulation and non-target stimulation were analyzed by t-test. Pearson coefficient analysis of correlation between eye movement parameters that had differences was conducted. The effectiveness of eye movement parameters to distinguish between the experimental group and the control group was calculated by the receiver operator characteristic （ROC） curve. Results Participants from the experimental group had shorter average pupil diameter, longer average fixation duration and fewer fixation points （P<0.05）, but the differences in blink frequency had no statistical significance. The differences in the above indicators of the control group in observing target stimulation and non-target stimulation had no statistical significance. The average fixation duration showed a negative correlation with fixation points （r=-0.255, P<0.05）; the average fixation duration showed a negative correlation with average pupil diameter （r=-0.218, P<0.05）; the fixation points showed a positive correlation with average pupil diameter （r=0.09, P<0.05）. The area under the curve of average pupil diameter, average fixation duration and fixation points was 0.603, 0.621 and 0.580, respectively. Conclusion The average pupil diameter, average fixation duration and fixation points obtained by the eye tracker under laboratory conditions can be used to detect lies.
Subject(s)
Humans , Algorithms , Eye Movements , Lie Detection , Pupil , Time FactorsABSTRACT
Objective To explore polygraph accuracy of Control Question Test （CQT）and whether it could be influenced by examinee's education level and type of violation of law. Methods Real cases of CQT （n=104） and the data from MAO （n=296） were collected. The polygraph accuracy of CQT was calculated. Variance analysis on three groups of different education levels was used to compare their age, and then the chi-square test was employed to compare polygraph accuracy among the groups. Independent sample t test was used to compare the age of subjects in the two groups of different types of violation of law, and then chi-square test was used to compare the true positive rate and true negative rate of lie detection after integration. Results In CQT lie detection of criminal cases, the true positive rate was 87.00%, the false negative rate was 13.00%, the true negative rate was 82.20%, and the false positive rate was 17.80%. There was no statistical significance in the differences between the true positive rate and the true negative rate （P>0.05）. In CQT lie detection of the groups of different education levels, there was no statistical significance in the differences between the true positive rates （P>0.05） while the differences between the true negative rates had statistical significance （P<0.05）. There was no statistical significance in the differences of both the true positive rates and the true negative rates between the violent violation of law and non-violent violation of law （P>0.05）. Conclusion There is no significant difference between the efficiency of CQT lie detection of identifying criminals and excluding innocents. However, a comparatively high false positive rate and false negative rate still exist. The efficiency of CQT lie detection identifying criminals may not influenced by the examinee's education level and type of violation of law, but its efficiency of excluding innocents may be influenced by the examinee's education level.
Subject(s)
Criminals , Lie Detection , Monitoring, Physiologic , PsychophysiologyABSTRACT
Since the early 2000s, there has been a continued interest in lie detection using functional magnetic resonance imaging (fMRI) in neuroscience and forensic sciences, as well as in newly emerging fields including neuroethics and neurolaw. Related fMRI studies have revealed converging evidence that brain regions including the prefrontal cortex, anterior cingulate cortex, parietal cortex, and anterior insula are associated with deceptive behavior. However, fMRI-based lie detection has thus far not been generally accepted as evidence in court, as methodological shortcomings, generalizability issues, and ethical and legal concerns are yet to be resolved. In the present review, we aim to illustrate these achievements and limitations of fMRI-based lie detection.
Subject(s)
Brain , Deception , Forensic Sciences , Gyrus Cinguli , Lie Detection , Magnetic Resonance Imaging , Neurosciences , Prefrontal Cortex , RabeprazoleABSTRACT
Objective:To explore the roles of cognition and deception in the Guilty Knowledge Tests and its effectiveness on the judgement of the guilt and the informed innocent people.Methods:72 healthy undergraduates participated in the study and were randomly assigned to the experimental conditions.This research was composed of one laboratory experiment with the mork crime paradigm in GKT, and the widely measured electrodermal responses(EDRs) as the physiological index.Three response modes were designed in the experiment in order to test the existence of cognition and deception components.Results:Significant differences of judgement scores were observed in different reponse modes and different roles.Conclusion:Deception plays a more important role than cognition in GKT.However, GKT can not efficiently discriminate the guilty and informed innocent people and needs futher exploration.
ABSTRACT
Dentro de la práctica clínica diaria, así como en la actividad forense, con frecuencia es necesaria la realización de entrevistas que permitan obtener de información veraz y fiable, con el fin de adoptar conductas consecuentes; sin embargo, en muchas ocasiones se encuentra a un sujeto entrevistado que puede ganar algo respecto de la conducta que va a seguir, según la información que brinde, y tenderá a manipular la información que entrega o a engañar de manera deliberada. Hay entrevistadores que, por su trabajo y experticia, son capaces de reconocer los indicadores de engaño; pero no todos lo hacen. En esta revisión se describen algunas claves que pueden facilitar el ejercicio profesional a aquellos quienes en su práctica se ven enfrentados a la manipulación de información o a la simulación de trastornos mentales.
Both in everyday clinical practice and forensic settings, mental health professionals have to conduct interviews to obtain reliable and valid information in order to make decisions and take measures. However, sometimes, professionals are faced with subjects who may try to find some benefit from the interview by manipulating the data provided and deliberately deceiving the rater. Certain raters, given their experience and expertise, are able to detect these deceit markers or signs, but others are not. This paper offers a reviews of some key factors that may be helpful for those professionals who are confronted with information manipulation as well as mental disorders malingering.
ABSTRACT
Lie detection techniques are utilized by investigating agencies in a wide variety of fields, such as Defence, Secret Services, Terrorism, as the veracity of statements cannot be taken at face value.
ABSTRACT
Objective: To confirm the cognitive rationale of Guilty Knowledge Test (GKT) with a polygraph lie-detection test,explore the merits of GKT's variation as narrowing unclear range of guilty knowledge, and to discuss the problems of the commonly used scoring method which was introduced by Lykken initially in order to obtain more scientific scoring method in accordance with the cognitive rationale. Methods:40 college students were chosen as participants.The study was designed under non-motivational instructions and neutral materials of meaningless letter strings. Results: The lie detection accuracy of this research was 73% under standard GKT paradigm (namely, the tester knowing the guilty knowledge clearly) with the scoring method introduced by Lykken, which confirmed the cognitive rationale of GKT. The accuracy of reducing guilty knowledge range from 5 to 2 was 78.4% in the condition of unclear-clue GKT (namely, the tester only knowing the guilty knowledge in the range of five items) with the scoring method of height and vicinity.Conclusion: The accuracy of lie detection with standard GKT in this study is similar to top accuracies of foreign studies with the same pattern and verified the rationale of cognition for GKT. The innovative scoring method suggested in this paper bears merits in application and is worth further studying.
ABSTRACT
In an EEG study of event—related potentials(REP),40 healthy volunteers partici-pated in a preliminary experiment for lie detection.This experiment required the subjects to answerwhether recognize some one in a random photo—showing.A positive rate of 95% and a false negativerate of 5% were found in this experiment.The amplitudes and area of P_(300) were proved,though prelimi-nary,to serve as an objective ground for lie detection no matter what the answer the subject made.