PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Lie Detection”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1991

The truth will out: interrogative polygraphy ("lie detection") with event-related brain potentials.

The feasibility of using Event Related Brain Potentials (ERPs) in Interrogative Polygraphy ("Lie Detection") was tested by examining the effectiveness of the Guilty Knowledge Test designed by Farwell and Donchin (1986, 1988). The subject is assigned an arbitrary task requiring discrimination between experimenter-designated targets and other, irrelevant stimuli. A group of diagnostic items ("probes"), which to the unwitting are indistinguishable from the irrelevant items, are embedded among the irrelevant. For subjects who possess "guilty knowledge" these probes are distinct from the irrelevants and are likely to elicit a P300, thus revealing their possessing the special knowledge that allows them to differentiate the probes from the irrelevants. We report two experiments in which this paradigm was tested. In Experiment 1, 20 subjects participated in one of two mock espionage scenarios and were tested for their knowledge of both scenarios. All stimuli consisted of short phrases presented for 300 ms each at an interstimulus interval of 1550 ms. A set of items were designated as "targets" and appeared on 17% of the trials. Probes related to the scenarios also appeared on 17% of the trials. The rest of the items were irrelevants. Subjects responded by pressing one switch following targets, and the other following irrelevants (and, of course, probes). ERPs were recorded from FZ, CZ, and PZ. As predicted, targets elicited large P300s in all subjects. Probes associated with a given scenario elicited a P300 in subjects who participated in that scenario. A bootstrapping method was used to assess the quality of the decision for each subject. The algorithm declared the decision indeterminate in 12.5% of the cases. In all other cases a decision was made. There were no false positives and no false negatives: whenever a determination was made it was accurate. The second experiment was virtually identical to the first, with identical results, except that this time 4 subjects were tested, each of which had a minor brush with the law. Subjects were tested to determine whether they possessed information on their own "crimes." The results were as expected; the Guilty Knowledge Test determined correctly which subject possessed which information. The implications of these data both for the practice of Interrogative Polygraphy and the interpretation of the P300 are discussed.

Adult↗
PubMed1991

Who can catch a liar?

The ability to detect lying was evaluated in 509 people including law-enforcement personnel, such as members of the U.S. Secret Service, Central Intelligence Agency, Federal Bureau of Investigation, National Security Agency, Drug Enforcement Agency, California police and judges, as well as psychiatrists, college students, and working adults. A videotape showed 10 people who were either lying or telling the truth in describing their feelings. Only the Secret Service performed better than chance, and they were significantly more accurate than all of the other groups. When occupational group was disregarded, it was found that those who were accurate apparently used different behavioral clues and had different skills than those who were inaccurate.

Aptitude↗
PubMedDate not supplied

Why (some) Americans believe in the lie detector while others believe in the guilty knowledge test.

The accuracy of polygraphic lie detection in real life applications is very little better than chance. Yet, at least in the United States, many agencies and the polygraphers themselves have great faith in the technique. The reasons why polygraph examiners, and their clients, genuinely believe in the myth of the polygraph are explained and illustrated. A more plausible method of polygraphic interrogation, the Guilty Knowledge Test (GKT), is described and it is shown how the GKT, but not the lie test, might have resolved doubts about the case of Demjanjuk, the alleged "Ivan the Terrible."

Arousal↗
PubMed1976

[Significance of byssochlamic acid in fruit juice mold].

The authors describe a method for the determination of byssochlamic acid in fruit juice. After extraction and purification, byssochlamic acid is separated by thin-layer chromatography on HF 254 silica gel. The quenching of fluorescence of byssochlamic acid is estimated quantitatively on the plate by means of the thin-layer attachment of a fluorescence spectrophotometer using reference substances. For fruit juices the recovery rate is 80%; the limit of detection lies at 0.5 p.p.m. Byssochlamic acid could not be detected in commercially-available fruit juice and neither in juices produced of fruits which had spontaneously got mouldy.

Food Analysis↗
PubMed1976

[Rapid enzymatic-colorimetric method for detecting organophosphorous insecticide residues in milk].

The authors developed a new enzymatic-colorimetric rapid method for testing milk for residues of organophosphorous insecticides. The test is based on the colour reaction of indoxyl acetate with the esterase of the OROSERAN (Dessau) horse serum which is inhibited by organophosphorous insecticides. Calibration curves were established for Trichlorphon and Dichlorphos (DDVP). The limit of detection lies at 0.02 mg/kg. The time actually needed per sample is about 15 min. The result is obtained within 90 min. Since this procedure requires no clean-up operations, it is labour-saving compared to other thin-layer or gas chromatographic methods. It may be recommended as a screening test for the detection of organophosphorous insecticides in milk samples.

Animals↗
PubMed1979

[Determination of aluminum in foods].

In connection with studies on the changes of functional properties of food constituents (e. g. solubility of proteins) by means of aluminium compounds, the elaboration of an appropriate method for the quantitative determination of aluminium has been necessary. The organic samples are mineralized with 80% perchloric acid; in case of fat-containing foods, after fat removal. After reaction with aluminon (ammonium salt of aurin tricarboxylic acid), aluminium is determined photometrically at 530 nm. The limit of detection lies between 1 and 2 ppm; the recovery rate is 103%; the standard deviation is +/- 10%. The determination (without mineralization) requires about 1 hours. The authors analyzed, inter alia, milk (1.2--1.7 ppm A1), fat cheese (9 ppm), micora (4 ppm), aluminium-stabilized protein texturates (300--1500 ppm).

Aluminum↗
PubMed1975

[Preliminary investigations of the serum alpha-1-fetoprotein level in mature and premature newborn infants (author's transl)].

Semiquantitative determination of the serum AFP concentration was carried out in 170 newborn infants (mature and premature) by means of crossover electrophoresis on admission to hospital and at 1 to 2 weekly intervals thereafter. The infants were divided into 3 groups according to their birth weight and also grouped according to gestational age into 3 further groups. The serum AFP level was correlated with the age in weeks of the infants for each group separately. Mature newborn infants with a birth weight of over 2500 g show a rapid fall in serum AFP titre; AFP is no longer detectable after the 9th week of life. In premature infants with a birth weight of 1500 to 2500 g, the fall in AFP titre is delayed and reaches zero between the 7th and 13th week of age. There is a markedly slower decrease in serum AFP concentration in the group of immature infants with a birth weight of under 1500 g; the limit of detectability lies between the 13th and the 17th week of age. An almost identical pattern is revealed when the infants are grouped according to gestational age. The possibility of diagnosing the small for date babies and severe liver disease by means of the serum AFP titre is discussed.

Age Factors↗
PubMed1976

A psychophysiological study of determinants for detection of deception.

Three studies were conducted to obtain available data on the determinants for detection of deception rates. (a) Psychophysiological measures were evaluated for effectiveness in detecting deception. A relevant-irrelevant method was used with two conditions; neutral stimulus and personal stimulus. Of the physiological variables, skin potential response, skin resistance response, finger pulse volume, and skin blood flow were significant indicators of deception. (b) Three experiments were conducted to study the psychophysiological effects of false and true feedback of skin potential response on the detection rates. It was concluded that the subjects receiving information that they were detectable were easier to detect than the subjects who believed that they were not detected and the subjects who received feedback of actual responses. (c) With the use of skin potential response channel, significant detection rates were obtained for all experiments under the condition that subjects verbally lied by means of "No" responses. On the other hand, the subjects who were motivated to deceive produced differentially augmented responses in the absence of any verbal response and also when the subjects told the truth to critical items and lied to irrelevant ones.

Adolescent↗
PubMedDate not supplied

Science and the CQT polygraph. A theoretical critique.

Despite substantial contrary scientific evidence, polygraph tests to detect deception continue to be employed in the United States. It is argued that polygraph tests (in particular, the Control Question Technique) lack construct validity. Polygraph tests do not assess deceptiveness, but rather are situations designed to elicit and assess fear. Correct decisions may be obtained when subjects fear detection; however, because there is no way to determine the cause of a subject's fear or anxiety, validation is impossible. The paper also considers other physiological detection paradigms and concludes that because of the nature of honesty their use to detect deception is unlikely.

Arousal↗