Use of antianxiety drugs as countermeasures in the detection of guilty knowledge

Frequent Countermeasure Usage by Narcissistic Examinees in the Concealed Information Test

Narcissistic dimensions and self-assessed lie and truth-telling and detecting abilities were used to predict deliberate attempts to influence the outcomes of the Concealed Information polygraph Test. In this study, which used a fabricated murder scenario, 241 examinees were randomly allocated to four experimental conditions in a 2 × 2 factorial design. Two guilt conditions (guilty and innocent) were crossed with two countermeasures conditions (with or without countermeasure instructions). One group consisted of 120 informed guilty participants who were offered the opportunity to give a false response to neutral items by verbally answering "yes," by which they falsely confirmed that the item is relevant to the murder case. Participants were told that frequent lying would confuse the polygraph and help them pass the test. Another informed guilty group (41 participants) was not given the opportunity to use countermeasures. Two control groups of 40 participants each were unaware of the critical items. One control group used countermeasures while the other did not. Narcissistic dimensions and self-assessed lie-telling ability correlated positively with frequent use of countermeasures. Conflicting results about the relation between countermeasure usage and physiological responses to critical items were obtained.

Diagnosing Estimate Distortion Due to Significance Testing in Literature on Detection of Deception

Studies journals typically report or feature results significant by statistical test criterion. This is a bias that prevents obtaining precise estimates of the magnitude of any underlying effect. It is severe with small effect sizes and small numbers of measurements. To illustrate the problem and a diagnosis technique, results of published studies on the detection of deception are graphed. The literature contains large effect sizes affirming that deceptive responses in contrast to truthful responses are associated with more reactive Skin Resistance Responses. These effect sizes when graphed on the x-axis against n on the y-axis are distributed as funnel graphs. A subset of studies show support for predicted small to medium effects on different physiological measures, individual differences, and condition manipulations. These effect sizes graphed by sample ns follow negative correlations, suggesting that effect sizes from published values of t, F, and z are exaggerations.

Drugs, sweat, and fears: a comparison of the effects of diazepam and methylphenidate on fear conditioning

RATIONALE

Classical conditioning of a fear response involves the formation of an association between a stimulus and an emotional response and can be seen as a basic form of emotional memory. While both benzodiazepines and stimulant drugs may influence the formation of episodic memories for emotional events, their effects on fear conditioning are less clear.

OBJECTIVES

This study compared the effects of diazepam with methylphenidate on fear conditioning.

MATERIALS AND METHODS

In a single-session between groups design with three conditions [placebo, diazepam (10 mg), and methylphenidate (40 mg)], classical conditioning of a skin conductance response to a visual stimulus previously paired with a 100-db white noise was tested in 45 healthy volunteers.

RESULTS

Diazepam blocked fear conditioning, despite responses to the unconditioned aversive stimulus and neutral control stimulus being unimpaired. Conditioning remained intact after methylphenidate. Conditioned responses were not extinguished completely by the end of the experiment, and it was not possible to draw conclusions about the effects of the drugs on extinction.

CONCLUSIONS

Although diazepam has well-documented amnesic effects, it has not been found to affect implicit forms of memory like perceptual and conceptual priming. As the present study found impaired fear conditioning after diazepam, it adds weight to recent findings that emotional memories are disproportionately impaired by the benzodiazepines.

The Guilty Knowledge Test and the modified Stroop task in detection of deception: an exploratory study

The current study tested whether a simple Stroop paradigm can be used to detect deceptive behavior. 40 university students (34 women), half of whom committed a mock crime, were administered a Guilty Knowledge Test and modified Stroop task to detect guilt or innocence. The Guilty Knowledge Test is a well-known psychophysiological detection method, which consists of multiple-choice questions about details of the crime while skin conductance is recorded. Subjects possessing guilty knowledge are expected to show enhanced differential responses to the relevant stimuli. The modified Stroop task required color-naming of colored words related to the mock crime or an irrelevant crime. Each version of the Stroop task was presented in story form. Subjects possessing guilty knowledge were expected to produce larger reaction times to the relevant version relative to the irrelevant version. The test correctly identified 100% of innocent participants and 78% of guilty participants. In contrast, Stroop interference. i.e., reaction times for irrelevant crime details subtracted from those for mock crime details, did not differentiate between the two groups, suggesting that the story form of the Stroop paradigm is not suitable for lie detection.

The validity of psychophysiological detection of information with the Guilty Knowledge Test: a meta-analytic review

The authors performed a meta-analysis based on 169 conditions, gathered from 80 laboratory studies, to estimate the validity of the Guilty Knowledge Test (GKT) with the electrodermal measure. The overall average effect size was 1.55, but there were considerable variations among studies. In particular, mock-crime studies produced the highest average effect size (2.09). Three additional moderators were identified: Motivational instructions, deceptive ("no") verbal responses, and the use of at least 5 questions were associated with enhanced validity. Finally, a set of 10 studies that best approximated applications of the GKT under optimal conditions produced an average effect size of 3.12. The authors discuss factors that might limit the generalizability of these results and recommend further research of the GKT in realistic setups.