Psychopathy, threat, and polygraph test accuracy

Patrick and Iacono (1989) evaluated the accuracy of the Control Question Test (CQT) with psychopathic prison inmates under a realistically threatening experimental context designed to address prior criticisms about the ecological validity of mock-crime polygraph research. The study found that guilty psychopaths were detected at the same high rate as non-psychopaths (87%, excluding inconclusives), but that innocent subjects were correctly identified at only 56% accuracy, with subjective threat-induced anxiety identified as the primary driver of false positive errors.

Controlled mock-crime laboratory study with 48 male prison inmates (24 psychopathic, 24 non-psychopathic, classified via Hare's Psychopathy Checklist), using a group contingency threat paradigm and standard CQT procedures scored by both the original examiner and an independent blind evaluator.

This 1989 study by Patrick and Iacono investigated whether psychopathic individuals could defeat polygraph tests under realistic threat conditions, addressing a major concern in criminal investigations. The researchers used a mock-crime paradigm with 48 male prison inmates (24 psychopathic, 24 non-psychopathic) classified using Hare's Psychopathy Checklist. A key innovation was implementing a group contingency threat where poor performance could result in lost bonuses and social consequences within the prison. The study directly responded to criticisms of earlier research by creating genuinely threatening conditions rather than reward-based incentives.

This research provides crucial insights for criminal investigators regarding polygraph reliability with psychopathic offenders, a population that represents a significant proportion of serious criminals and poses unique challenges for deception detection.

Background & Context

Among the most persistent concerns in applied polygraph science is whether the Control Question Test (CQT) retains its validity when administered to individuals with psychopathic personality traits. The popular belief — long held by law enforcement, legal practitioners, and the general public — is that psychopaths, characterized by emotional shallowness, fearlessness, absence of guilt, and chronic manipulativeness, are uniquely capable of defeating the polygraph. If true, this would represent a serious vulnerability in any investigative context where psychopathic offenders are examined.

The foundational study by Raskin and Hare (1978) had earlier suggested that psychopaths were detected at roughly the same rate as non-psychopaths in a mock-crime paradigm, but that work drew sharp criticism from David Lykken, who argued that the reward-based incentive structure of the experiment lacked the genuine threat environment of real-world criminal investigations. A constructive replication of the Raskin and Hare study was carried out in which subjects were tested regarding a mock theft under conditions of threat rather than reward. This is precisely the gap that Patrick and Iacono's 1989 study set out to close.

An important issue concerning the use of the polygraph test in criminal investigations is its accuracy with psychopathic individuals, who are reputed to be skilled liars and manipulators with a limited capacity for anxiety or guilt, and the possibility that psychopaths might be able to beat the lie detector is a concern, particularly in view of research suggesting that psychopaths constitute a sizable proportion of criminal offenders. Published in the Journal of Applied Psychology in 1989, this study by Christopher J. Patrick and William G. Iacono directly addressed whether genuine, realistic threat conditions would change the polygraph's effectiveness against this uniquely challenging population.

Research Design & Methodology

Subjects were 24 psychopathic and 24 nonpsychopathic male prison inmates. Within each diagnostic group, equal numbers of "guilty" and "innocent" subjects were tested by experienced professional polygraphers regarding their involvement in a mock theft by using standard control question procedures. The total sample therefore comprised 48 participants drawn from the same British Columbia correctional facility used in the original Raskin and Hare (1978) research.

Psychopathy classification was determined using the Psychopathy Checklist (PCL) developed by Robert Hare — a rigorous, well-validated clinical instrument. Physiological activity during the test was recorded simultaneously on laboratory and field model polygraphs to provide quantitative physiological data. Charts were scored by both the original examiner and a separate independent evaluator who examined only the chart data blind to examinee status, in order to test whether access to extra-polygraphic information produced a meaningful accuracy difference.

A key design innovation was the construction of a group contingency threat: a group contingency threat was devised in which subjects believed that their personal performance could decide benefits or penalties for the sample as a whole. Specifically, participants were told that if more than 10 of the 48 inmates were classified as deceptive, they would forfeit a group bonus and their names would be disclosed to the prison population — a threat with significant, tangible social consequences within the prison environment. This design directly addressed Lykken's criticism of the earlier work by elevating the stakes to a genuinely threatening level.

• Design type: Controlled laboratory analog (mock-crime paradigm)
• N = 48 male prison inmates (24 psychopathic, 24 non-psychopathic)
• Guilt status: Equal split within each diagnostic group (guilty vs. innocent)
• Scoring: Original examiner + independent blind evaluator
• Instruments: Simultaneous field and laboratory polygraph recording
• Diagnostic tool: Hare Psychopathy Checklist; structured interview; case record review
• Statistical analyses: Discriminant function analysis including STAI (anxiety), age, and Socialization (So) scale scores

Results & Key Findings

The headline result: psychopaths were detected just as easily as non-psychopaths. Guilty psychopaths were detected just as easily as guilty nonpsychopaths, and the majority of guilty subjects (87%, excluding inconclusives) were correctly identified. However, innocent subjects were identified with only 56% accuracy, and an analysis of false positive errors suggested that the subjective impact of the threat was a critical factor in these outcomes.

The disparity between guilty and innocent detection rates is one of the study's most consequential findings. While the CQT reliably identified deceptive subjects — regardless of psychopathy diagnosis — its performance with innocent subjects was notably poor and barely above chance. The threat manipulation appeared to induce sufficient physiological arousal in innocent subjects that the test misclassified a substantial portion of them as deceptive.

• Overall hit rate for guilty subjects: 87% (excluding inconclusives)
• Innocent subject identification accuracy: 56% — near chance level
• Guilty psychopaths vs. non-psychopaths: No significant difference in detection rates
• Inter-rater agreement (original vs. blind evaluator): 87%
• Pretest guilt judgments by examiners: Did not exceed chance — ruling out extra-polygraphic contamination
• Discriminant function analysis: The analysis produced a significant discriminant function, F(3, 14) = 4.60, p < .05, with STAI score, age, and So score contributing to the equation, with STAI score showing a significant univariate effect, F(1, 16) = 6.21, p < .05.

The anxiety measure (STAI State score) proved most predictive of false positive errors among innocent subjects, suggesting that subjective threat perception — not psychopathy — was the primary driver of false positive outcomes. Socialization level contributed mainly as a suppressor variable, while psychopathy diagnosis itself showed no main effect on accuracy.

Discussion & Significance

The Patrick and Iacono (1989) findings carry profound theoretical and practical weight. By demonstrating that research on psychopathy and deception has not found any significant differences between psychopaths and controls in polygraph detection rates, the study forcefully challenges the widespread myth that psychopaths can systematically fool the polygraph. The CQT appears robust enough to detect deception in psychopathic individuals, likely because — even in the absence of guilt or anxiety — psychopaths respond to the cognitive demands of the examination. As Hare, Forth, and Hart (1989) proposed, their physiological responses may reflect perceptual-cognitive processing rather than fear or remorse.

Equally important, however, is what the study revealed about innocent subjects under threat. The 56% accuracy rate for innocents is a serious indictment of the CQT's ability to protect truthful individuals when high-stakes threat conditions are present. The discriminant function analysis confirmed that state anxiety — not psychopathy — was responsible for false positive errors, meaning that ordinary, non-psychopathic innocent individuals were put at greatest risk by the threat manipulation. This finding directly implicates the CQT's theoretical basis: the test relies on differential fear/arousal to relevant vs. comparison questions, but when global anxiety is elevated by situational threat, this differential response may collapse for innocent subjects.

Together, Patrick and Iacono conceived of a novel study to test the hypothesis that psychopathic individuals, owing to deficits in emotions such as remorse and fear, would be able to pass a polygraphic lie detector test even when guilty — and findings from this study fueled a desire to delve deeper into the nature of affective deficits in psychopathy. The work became a landmark reference point for subsequent scholarship on individual differences and polygraph accuracy, and is cited in the National Research Council's authoritative 2003 review of polygraph science.

Limitations & Considerations

Several important methodological boundaries constrain the generalizability of these findings:

• Analog design: All participants knew they were in a study; despite the threat manipulation, no subject faced genuine legal jeopardy, limiting ecological validity.
• Sample composition: The study used exclusively male prison inmates, restricting generalizability to women, community populations, or non-incarcerated psychopaths.
• Small cell sizes: With only 12 guilty and 12 innocent subjects per diagnostic group, the study has limited statistical power to detect small within-group differences.
• Screening stringency: A total of 107 inmates were screened to produce the final sample of 48, potentially creating a select and unrepresentative psychopathy sample.
• Threat vs. real-world stakes: Even a well-crafted group contingency threat may not fully replicate the psychological weight of actual criminal prosecution, incarceration, or career consequences faced in real polygraph examinations.
• CQT format only: Findings speak to the Comparison Question Test specifically; results may differ for the Concealed Information Test (CIT) or other polygraph formats, which operate on different theoretical mechanisms.

The strikingly low innocent accuracy rate (56%) also warrants caution in interpretation. It may partly reflect the specific threat manipulation used, and it remains uncertain whether this rate would replicate in a more ecologically valid criminal investigation context where examiners use different pre-test preparation techniques to differentiate nervous-but-innocent from genuinely deceptive subjects.

Practical Applications

For polygraph practitioners, the most actionable takeaway from Patrick and Iacono (1989) is a double-edged one. On the positive side, examiners can be reasonably confident that psychopathy alone is not a "get out of jail free" card for deceptive subjects: the CQT detected guilty psychopaths at the same high rate as guilty non-psychopaths, debunking the professional folklore that psychopaths are immune to the polygraph. This supports the continued use of polygraph examinations in criminal investigations involving suspects who display antisocial or psychopathic traits.

However, the study's finding of alarmingly low innocent accuracy under threat conditions is a direct warning for practitioners who work in high-stakes environments. Examiners should be especially attentive to state anxiety in innocent examinees and must invest rigorously in pre-test preparation techniques designed to calibrate appropriate concern toward comparison questions rather than allowing global threat-based arousal to contaminate the test. The results underscore why proper test administration, standardized procedures, and thorough pre-test interviews are not optional — they are essential safeguards for protecting innocent individuals from false positive outcomes.