Backster's Either-Or Rule is a foundational principle in polygraph scoring, guiding how examiners weigh reactions; this guide explains its role in interpreting a lie detector test.
The Either-Or Rule (EOR) established by Cleve Backster circa 1960 remains one of the most studied scoring principles in polygraph science. This comprehensive guide examines its origins, theoretical foundation, practical application in numerical scoring, research validation, and ongoing significance for polygraph examiners, attorneys, and anyone seeking to understand how comparison question polygraph testing works.
TL;DR — The Short Version
- Either-Or Rule — Backster's principle states that a subject's physiological responses will be predominantly stronger to either relevant questions (deception indicated) or comparison questions (truthfulness indicated), creating a binary pattern for scoring.
- Research by Meiron, Krapohl, and Ashkenazi (2008) found that applying the Either-Or Rule increased correct decisions from 70% to 80% and reduced inconclusive outcomes from 27% to 17% — all improvement attributable to better detection of deceptive cases.
- Psychological Set — The theoretical basis holds that an examinee's greatest psychological concern will drive their strongest autonomic nervous system responses during testing.
- Foundation of Modern Techniques — The Zone Comparison Test (ZCT), Matte Quadri-Track ZCT, Utah ZCT, and Federal ZCT all incorporate the comparison principle that Backster formalized.
- The 2011 APA Meta-Analytic Survey found that validated polygraph techniques produced an aggregated decision accuracy of 87% with a confidence interval of 80%–94% across 38 studies and 3,723 examinations.
- Modern computerized scoring systems such as the OSS-3 and ESS have digitized the comparison principle, using algorithms to quantify response differences with greater precision than manual scoring alone.
Who This Guide Is For
- Polygraph examiners and students learning validated testing methodologies
- Law enforcement professionals who use or rely on polygraph results
- Attorneys who need to understand the scientific basis of polygraph evidence
- Psychology researchers studying deception detection mechanisms
- Individuals preparing for a polygraph examination who want to understand the process
- Criminal justice professionals involved in PCSOT or pre-employment screening
Origins and Historical Context of the Either-Or Rule
Cleve Backster and the Evolution of Polygraph Science
The Either-Or Rule begins with Cleve Backster (February 27, 1924 – June 24, 2013), one of the most influential figures in polygraph history [3]Verified Cleve Backster — Wikipedia
Confirms Backster's biographical details (1924–2013), CIA background, founding of the Backster School of Lie Detection, and development of the Zone Comparison Technique. Born in Lafayette Township, New Jersey, Backster enlisted in the U.S. Navy in January 1943 and served through World War II [3]Verified Cleve Backster — Wikipedia
Confirms Backster's biographical details (1924–2013), CIA background, founding of the Backster School of Lie Detection, and development of the Zone Comparison Technique. After his naval discharge, he briefly served in the U.S. Army Counter Intelligence Corps, where he specialized in interrogation techniques [3]Verified Cleve Backster — Wikipedia
Confirms Backster's biographical details (1924–2013), CIA background, founding of the Backster School of Lie Detection, and development of the Zone Comparison Technique. In 1948, Backster joined the Central Intelligence Agency in Washington, DC, where he received training from Leonarde Keeler — one of the original developers of polygraph use — and helped establish the CIA's polygraph examination program [3]Verified Cleve Backster — Wikipedia
Confirms Backster's biographical details (1924–2013), CIA background, founding of the Backster School of Lie Detection, and development of the Zone Comparison Technique.
In 1960, Backster founded the Backster School of Lie Detection in New York City, which became one of the premier polygraph training institutions in the world [3]Verified Cleve Backster — Wikipedia
Confirms Backster's biographical details (1924–2013), CIA background, founding of the Backster School of Lie Detection, and development of the Zone Comparison Technique. The school trained law enforcement officers from agencies across the country in the use of the polygraph [3]Verified Cleve Backster — Wikipedia
Confirms Backster's biographical details (1924–2013), CIA background, founding of the Backster School of Lie Detection, and development of the Zone Comparison Technique. For more on the history of polygraph training institutions, see our guide to the Keeler Polygraph Institute.
Before Backster's contributions around 1960, polygraph examinations relied on the Relevant-Irrelevant (R-I) test format developed by John A. Larson and Leonarde Keeler. In the R-I approach, examiners compared responses to relevant questions with irrelevant, neutral questions. The fundamental weakness of this method was the lack of a meaningful baseline — irrelevant questions generated virtually no physiological arousal in anyone, meaning nearly any subject would show stronger reactions to relevant questions regardless of deception.
John E. Reid began addressing this limitation in 1947 by introducing comparison questions — questions designed to be mildly threatening to all examinees [12]Verified Truth and Deception: The Polygraph ('Lie-Detector') Technique
Confirms the comparison question technique was first developed in 1947 and describes the CQT methodology comparing different question types. Reid's revised questioning technique was essentially the birth of the comparison question and set the stage for more objective scoring of polygraph charts [5]Verified A Comparison of the Backster Scoring and Traditional Federal Scoring Using Computerized Analysis
Confirms Backster was the first to apply a positive and negative scoring system comparing relevant against comparison questions, and documents the EOR versus Federal scoring methods. However, it was Backster who formalized and refined this comparison methodology into a structured, teachable system with a numerical scoring framework [5]Verified A Comparison of the Backster Scoring and Traditional Federal Scoring Using Computerized Analysis
Confirms Backster was the first to apply a positive and negative scoring system comparing relevant against comparison questions, and documents the EOR versus Federal scoring methods.
The Paradigm Shift in Polygraph Interpretation
Until 1960, when Cleve Backster introduced the Backster Zone Comparison Technique, examiners evaluated polygraph charts using the "Clinical Approach" or "Global Analysis" technique — a subjective method that considered behavioral observations alongside physiological data [4]Verified Psychological Structure and Theoretical Concept of the Backster Zone Comparison Technique and the Quadri-Track Zone Comparison Technique
Confirms the theoretical concept and psychological structure of the Backster Zone Comparison Technique and its relationship to derivative techniques. Backster's innovation was transformative: he introduced a within-subject comparison model with a numerical scoring system [5]Verified A Comparison of the Backster Scoring and Traditional Federal Scoring Using Computerized Analysis
Confirms Backster was the first to apply a positive and negative scoring system comparing relevant against comparison questions, and documents the EOR versus Federal scoring methods.
Instead of asking "Did this person react strongly to the relevant question?" the examiner now asked "Did this person react more strongly to the relevant question or the comparison question?" This relative comparison controlled for individual differences in reactivity, nervous system sensitivity, and general test anxiety — factors that had previously confounded results.
Backster was the first to apply a positive and negative scoring system comparing the relevant questions against the comparison questions [5]Verified A Comparison of the Backster Scoring and Traditional Federal Scoring Using Computerized Analysis
Confirms Backster was the first to apply a positive and negative scoring system comparing relevant against comparison questions, and documents the EOR versus Federal scoring methods. His 1963 publication, "Standardized Polygraph Notepack and Technique Guide: Backster Zone Comparison Technique," provided the first highly standardized rationale and structure for the administration and scoring of a comparison question technique [7]Verified Standardized Polygraph Notepack and Technique Guide: Backster Zone Comparison Technique
Confirms the 1963 publication as the first highly standardized rationale and structure for the administration and scoring of a comparison question technique. The Backster Zone Comparison Technique was the first polygraph interpretation system to use a numerical evaluation and remains in wide use today [4]Verified Psychological Structure and Theoretical Concept of the Backster Zone Comparison Technique and the Quadri-Track Zone Comparison Technique
Confirms the theoretical concept and psychological structure of the Backster Zone Comparison Technique and its relationship to derivative techniques.
Circa 1960, Backster developed his numerical approach to scoring polygraph charts, which has been widely adopted by the polygraph community, as well as the Zone Comparison Technique, variations of which are still commonly used and taught at polygraph schools including the U.S. government's National Center for Credibility Assessment [3]Verified Cleve Backster — Wikipedia
Confirms Backster's biographical details (1924–2013), CIA background, founding of the Backster School of Lie Detection, and development of the Zone Comparison Technique. To learn more about the career path for polygraph examiners, visit our dedicated guide.
Theoretical Foundation: Psychological Set Theory
Understanding Psychological Set in Polygraph Science
The Either-Or Rule rests on a theoretical framework that Backster called "Psychological Set." This concept is central to understanding why the rule works and how it should be applied in practice.
Psychological Set theory posits that during a polygraph examination, an examinee's attention and emotional concern will be directed primarily toward whichever category of questions poses the greatest perceived threat to their well-being. The Backster Zone Comparison You-Phase Technique is a true single-issue test that offers two threats to the examinee who must choose which of those two threats presents the greatest peril to their security and well-being [6]Verified A Field Study of the Backster Zone Comparison Technique's Either-Or Rule and Scoring System Versus Two Other Scoring Systems When Relevant Question Elicits Strong Response
Analyzed the comparative effectiveness of the Backster Either-Or Rule versus Federal and Matte Quadri-Track scoring systems, finding EOR produced fewest inconclusives with no errors when relevant questions elicited strong responses.
The first threat comprises the relevant questions dealing with the specific issue under investigation. The second threat is in the form of comparison questions dealing with earlier-in-life activities that the examinee wishes to conceal from the polygraphist [6]Verified A Field Study of the Backster Zone Comparison Technique's Either-Or Rule and Scoring System Versus Two Other Scoring Systems When Relevant Question Elicits Strong Response
Analyzed the comparative effectiveness of the Backster Either-Or Rule versus Federal and Matte Quadri-Track scoring systems, finding EOR produced fewest inconclusives with no errors when relevant questions elicited strong responses. In order for the examinee to be given a clear choice between those two threats, a time bar is used to clearly separate the time period covered by the comparison questions from the time period covered by the relevant questions [6]Verified A Field Study of the Backster Zone Comparison Technique's Either-Or Rule and Scoring System Versus Two Other Scoring Systems When Relevant Question Elicits Strong Response
Analyzed the comparative effectiveness of the Backster Either-Or Rule versus Federal and Matte Quadri-Track scoring systems, finding EOR produced fewest inconclusives with no errors when relevant questions elicited strong responses.
For a deceptive person, the relevant questions represent the greatest threat because these questions directly address the behavior they are trying to conceal. For a truthful person, the comparison questions serve as the arena where their general test anxiety manifests most strongly, since these questions introduce uncertainty and mild concern about past behaviors. This psychological mechanism creates the binary pattern that gives the Either-Or Rule its name [1]Verified Practical Polygraph: A Survey and Description of Decision Rules
Documents the evolution from subjective to objective decision criteria in polygraph testing and their impact on reliability and accuracy. Understanding this mechanism is closely related to the Anticlimax Dampening Concept, another Backster contribution to polygraph theory.
The Autonomic Nervous System and Threat Response
The biological mechanism underlying the Either-Or Rule involves the autonomic nervous system (ANS), specifically the interplay between the sympathetic and parasympathetic branches. When a person perceives a psychological threat, the sympathetic nervous system activates measurable changes across multiple physiological systems simultaneously.
During a polygraph examination, these changes are recorded through multiple sensor types: pneumograph tubes measure respiratory patterns including rate, depth, and regularity of breathing; a cardio cuff records cardiovascular changes including relative blood pressure shifts, heart rate changes, and pulse amplitude variations; and galvanometers (EDA sensors) measure electrodermal activity — changes in skin conductance caused by sweat gland activity controlled by the sympathetic nervous system [13]Verified Credibility Assessment: Scientific Research and Applications
Comprehensive reference on credibility assessment methods including polygraph techniques, computerized systems, and countermeasure research. For a deeper understanding of how these measurements interact with testing procedures, see our guide on artifacts in polygraph testing.
The Either-Or Rule applies across all channels. In theory, a deceptive person should show stronger responses in all physiological channels to relevant questions, while a truthful person should show stronger responses to comparison questions. In practice, responses may vary across channels, which is why examiners collect multiple charts (typically a minimum of three) and use systematic scoring methods to evaluate the overall pattern [8]Verified An Assessment of the Backster 'Either-Or' Rule in Polygraph Scoring
Empirically tested Backster's EOR using 100 field cases; found EOR increased correct decisions from 70% to 80% and reduced inconclusives from 27% to 17%.
Control Questions vs. Relevant Questions Explained
The Architecture of Polygraph Question Types
To fully appreciate the Either-Or Rule, it is essential to understand the different categories of questions used in a polygraph test. The comparison question technique, first developed by John E. Reid in 1947, compares subjects' physiological responses to different types of questions [12]Verified Truth and Deception: The Polygraph ('Lie-Detector') Technique
Confirms the comparison question technique was first developed in 1947 and describes the CQT methodology comparing different question types. Modern comparison question tests typically employ four categories:
Relevant Questions are the heart of the investigation, directly addressing the specific issue or allegation being tested. They are formulated during the pretest interview to ensure there is no confusion about what is being asked and should be answerable with a simple "no" by a truthful person.
Comparison (Control) Questions are the innovative element introduced to create a meaningful baseline [12]Verified Truth and Deception: The Polygraph ('Lie-Detector') Technique
Confirms the comparison question technique was first developed in 1947 and describes the CQT methodology comparing different question types. These questions are broadly related to the same general category of behavior as the relevant questions but are not specifically tied to the incident under investigation. They are designed to elicit mild concern from truthful examinees and typically cover a wide time period. During the pretest interview, the examiner typically reviews these questions in a way that encourages the examinee to deny ever having engaged in the described behavior, creating a situation where the truthful examinee directs their Psychological Set toward the comparison questions.
Irrelevant (Neutral) Questions serve as buffers and orienting stimuli, allowing the examinee's physiological responses to return to baseline between relevant and comparison questions. These questions are not scored.
Sacrifice Relevant Questions are placed near the beginning of the question sequence and address the general topic of the investigation without being specific enough to trigger strong deceptive responses, helping orient the examinee to the topic and absorb initial reactivity [6]Verified A Field Study of the Backster Zone Comparison Technique's Either-Or Rule and Scoring System Versus Two Other Scoring Systems When Relevant Question Elicits Strong Response
Analyzed the comparative effectiveness of the Backster Either-Or Rule versus Federal and Matte Quadri-Track scoring systems, finding EOR produced fewest inconclusives with no errors when relevant questions elicited strong responses. For more on how examiners assess behavioral cues during questioning, see what behavior does a polygraph examiner look for. Learn also about the role of symptomatic questions in polygraph testing.
How the Either-Or Rule Works in Practice
The Binary Decision Model
The Either-Or Rule operates on a fundamentally binary decision model: an examinee's autonomic nervous system will direct its strongest responses toward either the relevant questions or the comparison questions. The Backster You-Phase uses the Either-Or Rule (EOR) to select the bracketing comparison tracing to score the relevant question against [5]Verified A Comparison of the Backster Scoring and Traditional Federal Scoring Using Computerized Analysis
Confirms Backster was the first to apply a positive and negative scoring system comparing relevant against comparison questions, and documents the EOR versus Federal scoring methods. In essence, the EOR permits scoring relevant question tracings against a stronger bracketing comparison tracing only [5]Verified A Comparison of the Backster Scoring and Traditional Federal Scoring Using Computerized Analysis
Confirms Backster was the first to apply a positive and negative scoring system comparing relevant against comparison questions, and documents the EOR versus Federal scoring methods.
This is not a matter of degree but of direction. The rule asserts that the pattern of responses will consistently favor one category over the other, and this consistency across multiple chart presentations and multiple physiological channels provides the basis for the examiner's opinion.
The Federal You-Phase scoring system, by contrast, always scores relevant question tracings against the stronger bracketing comparison question tracings regardless of the Either-Or principle [5]Verified A Comparison of the Backster Scoring and Traditional Federal Scoring Using Computerized Analysis
Confirms Backster was the first to apply a positive and negative scoring system comparing relevant against comparison questions, and documents the EOR versus Federal scoring methods. This methodological difference between Backster and Federal scoring approaches has been the subject of considerable research and professional discussion [8]Verified An Assessment of the Backster 'Either-Or' Rule in Polygraph Scoring
Empirically tested Backster's EOR using 100 field cases; found EOR increased correct decisions from 70% to 80% and reduced inconclusives from 27% to 17%. A key study by Dollins (2003) found the Backster scoring system produced larger negative values and an imbalance in conclusive scores compared to Utah and Federal systems [9]Verified Relative Efficacy of the Utah, Backster, and Federal Scoring Rules: A Preliminary Investigation
Found Backster scoring produced larger negative values and imbalance in conclusive scores compared to Utah and Federal systems, with no meaningful difference in false positive rates.
Numerical Scoring and Spot Analysis
Backster introduced a numerical scoring system to operationalize the Either-Or Rule. In this system, each comparison of a relevant question to its neighboring comparison question is assigned a score on a seven-position scale (typically +3 to -3, with 0 representing no discernible difference) [1]Verified Practical Polygraph: A Survey and Description of Decision Rules
Documents the evolution from subjective to objective decision criteria in polygraph testing and their impact on reliability and accuracy. Positive scores indicate that the comparison question produced a stronger response (suggesting truthfulness), while negative scores indicate that the relevant question produced a stronger response (suggesting deception).
The scoring works as follows for each physiological channel: +3 = Comparison question response is dramatically stronger; +2 = Comparison question response is noticeably stronger; +1 = Comparison question response is slightly stronger; 0 = No meaningful difference; -1 = Relevant question response is slightly stronger; -2 = Relevant question response is noticeably stronger; -3 = Relevant question response is dramatically stronger.
Each relevant-comparison pair is scored for each physiological channel in each chart. The scores are then summed to produce a grand total. If the grand total exceeds a positive threshold, the examinee is classified as non-deceptive (NDI). If it falls below a negative threshold, the classification is deceptive (DI). Scores between the thresholds result in an inconclusive (INC) outcome [1]Verified Practical Polygraph: A Survey and Description of Decision Rules
Documents the evolution from subjective to objective decision criteria in polygraph testing and their impact on reliability and accuracy[8]Verified An Assessment of the Backster 'Either-Or' Rule in Polygraph Scoring
Empirically tested Backster's EOR using 100 field cases; found EOR increased correct decisions from 70% to 80% and reduced inconclusives from 27% to 17%. Research has explored optimal cutscores and two-stage decision rules that maximize accuracy while minimizing inconclusive rates [1]Verified Practical Polygraph: A Survey and Description of Decision Rules
Documents the evolution from subjective to objective decision criteria in polygraph testing and their impact on reliability and accuracy[2]Verified Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms aggregated accuracy of 87% (CI 80%–94%) for validated polygraph techniques across 38 studies and 3,723 examinations[10]Verified New Decision Rule Development: Exploration of a Two-Stage Approach
The Two-Stage Rule successfully reduced inconclusive polygraph results while maintaining classification accuracy equivalent to the Grand Total Rule alone. Notably, Senter (2001) developed a Two-Stage Rule that successfully reduced inconclusive results while maintaining classification accuracy equivalent to the Grand Total Rule alone [10]Verified New Decision Rule Development: Exploration of a Two-Stage Approach
The Two-Stage Rule successfully reduced inconclusive polygraph results while maintaining classification accuracy equivalent to the Grand Total Rule alone. For a deeper exploration of how polygraph accuracy is measured and what it means for examiners and examinees, see our full analysis.
Research Validation and Accuracy Evidence
The Meiron, Krapohl, and Ashkenazi (2008) Assessment
The most significant research directly examining the Either-Or Rule was conducted by Meiron, Krapohl, and Ashkenazi (2008), published in the journal Polygraph (Volume 37, pages 240–249) [8]Verified An Assessment of the Backster 'Either-Or' Rule in Polygraph Scoring
Empirically tested Backster's EOR using 100 field cases; found EOR increased correct decisions from 70% to 80% and reduced inconclusives from 27% to 17%. The study investigated the EOR using 100 Backster field cases which were blind scored by field examiners who used either the Backster scoring system or the U.S. Federal scoring system.
The results showed that without the EOR, Backster scorers made an average of 70% correct decisions, 3% errors, and 27% inconclusive results. With the EOR applied, they rendered an average of 80% correct decisions, 3% errors, and only 17% inconclusives [8]Verified An Assessment of the Backster 'Either-Or' Rule in Polygraph Scoring
Empirically tested Backster's EOR using 100 field cases; found EOR increased correct decisions from 70% to 80% and reduced inconclusives from 27% to 17%. Critically, all of the increase in decision accuracy and reduction in inconclusive rate was attributable to improvement in classifying deceptive cases [8]Verified An Assessment of the Backster 'Either-Or' Rule in Polygraph Scoring
Empirically tested Backster's EOR using 100 field cases; found EOR increased correct decisions from 70% to 80% and reduced inconclusives from 27% to 17%.
While the EOR showed promising sensitivity (ability to correctly identify deceptive subjects), the study also noted a deficient specificity (ability to correctly identify truthful subjects) [8]Verified An Assessment of the Backster 'Either-Or' Rule in Polygraph Scoring
Empirically tested Backster's EOR using 100 field cases; found EOR increased correct decisions from 70% to 80% and reduced inconclusives from 27% to 17%. This nuanced finding provides valuable guidance for examiners: the EOR appears most beneficial in reducing inconclusive outcomes and increasing the detection of deception, while examiners should remain attentive to the potential for specificity limitations.
The Matte (2010) Field Study
James Allan Matte (2010) published a field study in European Polygraph comparing the Backster Either-Or Rule and scoring system against two other scoring systems — the Federal scoring system and the Matte Quadri-Track system — specifically when a relevant question elicited a strong response [6]Verified A Field Study of the Backster Zone Comparison Technique's Either-Or Rule and Scoring System Versus Two Other Scoring Systems When Relevant Question Elicits Strong Response
Analyzed the comparative effectiveness of the Backster Either-Or Rule versus Federal and Matte Quadri-Track scoring systems, finding EOR produced fewest inconclusives with no errors when relevant questions elicited strong responses. This study revealed that the use of Backster's Either-Or Rule and concept produced the least number of inconclusives and no errors when compared with the other two scoring systems in the specific scenario of strong relevant question responses [6]Verified A Field Study of the Backster Zone Comparison Technique's Either-Or Rule and Scoring System Versus Two Other Scoring Systems When Relevant Question Elicits Strong Response
Analyzed the comparative effectiveness of the Backster Either-Or Rule versus Federal and Matte Quadri-Track scoring systems, finding EOR produced fewest inconclusives with no errors when relevant questions elicited strong responses.
This research highlighted an important practical advantage: in cases where relevant questions produced particularly strong physiological responses, the EOR's mechanism for selecting the appropriate comparison question for scoring proved especially effective at maintaining accuracy [6]Verified A Field Study of the Backster Zone Comparison Technique's Either-Or Rule and Scoring System Versus Two Other Scoring Systems When Relevant Question Elicits Strong Response
Analyzed the comparative effectiveness of the Backster Either-Or Rule versus Federal and Matte Quadri-Track scoring systems, finding EOR produced fewest inconclusives with no errors when relevant questions elicited strong responses.
Comparative Scoring System Research
Multiple studies have examined how the Backster scoring system compares to alternatives. Dollins (2003) conducted a preliminary investigation into the relative efficacy of the Utah, Backster, and Federal scoring rules, finding that the Backster scoring system produced larger negative values and an imbalance in conclusive scores compared to Utah and Federal systems, though no meaningful difference in false positive rates was observed [9]Verified Relative Efficacy of the Utah, Backster, and Federal Scoring Rules: A Preliminary Investigation
Found Backster scoring produced larger negative values and imbalance in conclusive scores compared to Utah and Federal systems, with no meaningful difference in false positive rates.
Senter (2000) compared Utah and DoDPI scoring accuracy and found that when decision rules, chart number, and data channels were equated, DoDPI and Utah scorers showed no significant differences in accuracy [15]Verified Comparison of Utah and DoDPI Scoring Accuracy
Found no significant differences in accuracy between DoDPI and Utah scorers when decision rules, chart number, and data channels were equated. This finding underscored that much of the variation in scoring outcomes relates to the specific decision rules applied rather than fundamental differences in examiner skill.
Nelson (2018) provided a comprehensive survey of decision rules used in modern polygraph testing, documenting the evolution from subjective to objective decision criteria and their impact on reliability and accuracy [1]Verified Practical Polygraph: A Survey and Description of Decision Rules
Documents the evolution from subjective to objective decision criteria in polygraph testing and their impact on reliability and accuracy. This work established that the field has progressively moved toward standardized, evidence-based scoring approaches — a trajectory that Backster's numerical system helped initiate.
Dutton (2018) further advanced the field by demonstrating that weighted EDA scores alone reduced inconclusive results by 49%, while combining EDA weighting with multinomial cut-scores achieved a 72% reduction in inconclusive outcomes [18]Verified Reducing Inconclusive Results: A Descriptive Analysis of Decision Rules, Weighted Electrodermal Scores and Multinomial Cut-Scores
Weighted EDA scores alone reduced inconclusive results by 49%, while combining EDA weighting with multinomial cut-scores achieved a 72% reduction.
APA Meta-Analytic Findings
The 2011 APA Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques represents the most comprehensive aggregation of polygraph accuracy data to date [2]Verified Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms aggregated accuracy of 87% (CI 80%–94%) for validated polygraph techniques across 38 studies and 3,723 examinations. The report examined 38 studies that met rigorous qualitative and quantitative inclusion criteria, encompassing 32 different samples and 45 different experiments and surveys [2]Verified Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms aggregated accuracy of 87% (CI 80%–94%) for validated polygraph techniques across 38 studies and 3,723 examinations. They included 295 scorers who provided 11,737 scored results of 3,723 examinations [2]Verified Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms aggregated accuracy of 87% (CI 80%–94%) for validated polygraph techniques across 38 studies and 3,723 examinations.
The data showed that event-specific (single-issue) diagnostic techniques — the type most directly aligned with the Backster Zone Comparison model — produced an aggregated decision accuracy of 89% (CI 83%–95%) with an inconclusive rate of 11% [2]Verified Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms aggregated accuracy of 87% (CI 80%–94%) for validated polygraph techniques across 38 studies and 3,723 examinations. Multiple-issue techniques produced an aggregated accuracy of 85% (CI 77%–93%) with a 13% inconclusive rate [2]Verified Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms aggregated accuracy of 87% (CI 80%–94%) for validated polygraph techniques across 38 studies and 3,723 examinations. The combination of all validated techniques produced an overall decision accuracy of 87% (CI 80%–94%) with a 13% inconclusive rate [2]Verified Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms aggregated accuracy of 87% (CI 80%–94%) for validated polygraph techniques across 38 studies and 3,723 examinations.
A 2021 comprehensive meta-analysis by Honts et al., published in Applied Cognitive Psychology, captured 138 datasets and confirmed that prior reviews "generally produced overall accuracy estimates of over 85%" [14]Verified A Comprehensive Meta-Analysis of the Comparison Question Polygraph Test
Meta-analysis of 138 datasets confirming that prior CQT reviews generally produced overall accuracy estimates of over 85%, with motivation showing positive linear relationship with accuracy. The study found that motivation had a positive linear relationship with accuracy, suggesting that real-world examinations with high-stakes outcomes may produce even better results than laboratory settings [14]Verified A Comprehensive Meta-Analysis of the Comparison Question Polygraph Test
Meta-analysis of 138 datasets confirming that prior CQT reviews generally produced overall accuracy estimates of over 85%, with motivation showing positive linear relationship with accuracy.
Major Polygraph Techniques Based on the Either-Or Rule
The Family of Zone Comparison Techniques
The Either-Or Rule and the broader Backster Zone Comparison methodology have served as the foundation for an entire family of polygraph techniques. As Matte (2007) documented, the theoretical concept and psychological structure of the Backster Zone Comparison Technique serves as the wellspring from which several other single-issue polygraph techniques emerged [4]Verified Psychological Structure and Theoretical Concept of the Backster Zone Comparison Technique and the Quadri-Track Zone Comparison Technique
Confirms the theoretical concept and psychological structure of the Backster Zone Comparison Technique and its relationship to derivative techniques.
The Backster You-Phase Technique is the original event-specific single-issue comparison question format, and is the foundation from which derivative techniques have emerged [7]Verified Standardized Polygraph Notepack and Technique Guide: Backster Zone Comparison Technique
Confirms the 1963 publication as the first highly standardized rationale and structure for the administration and scoring of a comparison question technique. It employs a carefully structured sequence of relevant, comparison, irrelevant, and sacrifice relevant questions to maximize the psychological set effect.
The Federal Zone Comparison Technique (Federal ZCT) is a modification of the Backster ZCT taught by the U.S. Department of Defense and widely used by federal agencies [7]Verified Standardized Polygraph Notepack and Technique Guide: Backster Zone Comparison Technique
Confirms the 1963 publication as the first highly standardized rationale and structure for the administration and scoring of a comparison question technique. The key difference lies in the Federal approach to selecting comparison questions for scoring: it always scores against the stronger bracketing comparison, regardless of the Either-Or principle [5]Verified A Comparison of the Backster Scoring and Traditional Federal Scoring Using Computerized Analysis
Confirms Backster was the first to apply a positive and negative scoring system comparing relevant against comparison questions, and documents the EOR versus Federal scoring methods.
The Matte Quadri-Track Zone Comparison Technique is another derivative that restricts the comparison of each relevant question to the control question preceding it within the same track, making it non-selective rather than using the EOR's selective comparison approach [4]Verified Psychological Structure and Theoretical Concept of the Backster Zone Comparison Technique and the Quadri-Track Zone Comparison Technique
Confirms the theoretical concept and psychological structure of the Backster Zone Comparison Technique and its relationship to derivative techniques. The Matte technique also assigns a minus one score rather than a zero when the relevant question elicits a significant reaction and its neighboring control question also elicits an equally significant reaction [4]Verified Psychological Structure and Theoretical Concept of the Backster Zone Comparison Technique and the Quadri-Track Zone Comparison Technique
Confirms the theoretical concept and psychological structure of the Backster Zone Comparison Technique and its relationship to derivative techniques.
The Utah Zone Comparison Technique represents the approach developed at the University of Utah by David Raskin, Charles Honts, and John Kircher, which uses the Utah Numerical Scoring System with its own decision rules and methodology [15]Verified Comparison of Utah and DoDPI Scoring Accuracy
Found no significant differences in accuracy between DoDPI and Utah scorers when decision rules, chart number, and data channels were equated.
Modern Computerized Scoring Adaptations
The Digitization of the Comparison Principle
The comparison principle at the heart of the Either-Or Rule has been operationalized in several major computerized scoring systems that have transformed polygraph data analysis from a primarily subjective art into a more quantifiable science.
The Objective Scoring System Version 3 (OSS-3), developed by Nelson, Handler, and Krapohl, is one of the most widely validated computer scoring algorithms in polygraph practice [16]Verified Brute-Force Comparison: A Monte Carlo Study of the Objective Scoring System version 3 (OSS-3) and Human Polygraph Scorers
Describes the OSS-3 scoring algorithm and validates its performance against human polygraph scorers using brute-force statistical methods. The OSS-3 is based on sound polygraph testing principles derived from existing research, and uses measurements of "Kircher features" — physiological response features first described by researchers at the University of Utah during the 1980s [16]Verified Brute-Force Comparison: A Monte Carlo Study of the Objective Scoring System version 3 (OSS-3) and Human Polygraph Scorers
Describes the OSS-3 scoring algorithm and validates its performance against human polygraph scorers using brute-force statistical methods. Because the scores come from measurements, the OSS-3 eliminates subjectivity in chart interpretation and produces a probabilistic classifier for both diagnostic and screening polygraphs [16]Verified Brute-Force Comparison: A Monte Carlo Study of the Objective Scoring System version 3 (OSS-3) and Human Polygraph Scorers
Describes the OSS-3 scoring algorithm and validates its performance against human polygraph scorers using brute-force statistical methods. Lafayette Instrument Company bundles the OSS-3 algorithm with its LXSoftware platform [16]Verified Brute-Force Comparison: A Monte Carlo Study of the Objective Scoring System version 3 (OSS-3) and Human Polygraph Scorers
Describes the OSS-3 scoring algorithm and validates its performance against human polygraph scorers using brute-force statistical methods.
The Empirical Scoring System (ESS), also developed by Nelson and colleagues, provides another validated manual scoring and decision policy framework [16]Verified Brute-Force Comparison: A Monte Carlo Study of the Objective Scoring System version 3 (OSS-3) and Human Polygraph Scorers
Describes the OSS-3 scoring algorithm and validates its performance against human polygraph scorers using brute-force statistical methods. The ESS and its multinomial variant (ESS-M) have been the subject of cross-cultural replication and extension studies, demonstrating their generalizability across different examiner populations [16]Verified Brute-Force Comparison: A Monte Carlo Study of the Objective Scoring System version 3 (OSS-3) and Human Polygraph Scorers
Describes the OSS-3 scoring algorithm and validates its performance against human polygraph scorers using brute-force statistical methods.
The Computerized Polygraph System (CPS), developed by David Raskin and John Kircher at the University of Utah in the early 1990s, was the world's first fully automated polygraph system [17]Verified Computerized Polygraph System (CPS)
Confirms the CPS as the world's first fully automated polygraph system developed by Raskin and Kircher at the University of Utah, now in its fourth generation. The CPS uses a discriminant analysis algorithm that weighs and combines physiological measures to calculate the probability of deception [17]Verified Computerized Polygraph System (CPS)
Confirms the CPS as the world's first fully automated polygraph system developed by Raskin and Kircher at the University of Utah, now in its fourth generation. It remains in worldwide use today through Stoelting's CPS Elite polygraph systems [17]Verified Computerized Polygraph System (CPS)
Confirms the CPS as the world's first fully automated polygraph system developed by Raskin and Kircher at the University of Utah, now in its fourth generation.
PolyScore, another major algorithm available in some polygraph systems, uses features obtained through logistic regression to classify examinees [16]Verified Brute-Force Comparison: A Monte Carlo Study of the Objective Scoring System version 3 (OSS-3) and Human Polygraph Scorers
Describes the OSS-3 scoring algorithm and validates its performance against human polygraph scorers using brute-force statistical methods. These computerized systems share the fundamental comparison principle with Backster's original method — they compare responses to relevant and comparison questions and produce a statistical determination — but do so with mathematical precision and perfect reliability across repeated analyses.
Importance for Polygraph Examiner Training
Training Standards and the Either-Or Rule
Accredited polygraph training programs require a minimum of 400 hours of instruction, ensuring that new examiners develop both the theoretical understanding and practical skill needed to apply techniques like the Either-Or Rule effectively [19]Verified Basic Polygraph Examiner Course — PEAK CATC
Confirms APA-accredited basic polygraph examiner courses require a minimum of 400 hours of instruction. Programs such as PEAK Credibility Assessment Training Center — which has taken over the legacy of the Backster School of Lie Detection — teach students validated polygraph techniques including appropriate use of decision rules and scoring systems [19]Verified Basic Polygraph Examiner Course — PEAK CATC
Confirms APA-accredited basic polygraph examiner courses require a minimum of 400 hours of instruction.
The curriculum at accredited programs covers the psychological structure underlying the Backster Zone Comparison Technique, question construction principles, proper pretest interview procedures that establish psychological set, and both manual and computerized scoring methodologies. Students learn to analyze polygraph data using validated scoring systems and demonstrate proficiency in conducting examinations under field-like conditions [19]Verified Basic Polygraph Examiner Course — PEAK CATC
Confirms APA-accredited basic polygraph examiner courses require a minimum of 400 hours of instruction.
The Backster Zone Comparison Technique's theoretical framework requires that a structured pretest interview be administered in an unbiased manner that focuses on the relevant and comparison questions without inviting outside issues that can interfere with the examinee's psychological set [4]Verified Psychological Structure and Theoretical Concept of the Backster Zone Comparison Technique and the Quadri-Track Zone Comparison Technique
Confirms the theoretical concept and psychological structure of the Backster Zone Comparison Technique and its relationship to derivative techniques. Understanding this relationship between pretest procedures and the Either-Or Rule is essential for maintaining technique accuracy.
To explore the standards that govern polygraph practice, see our guides on APA standards for polygraph examiners and building examiner-examinee rapport. Professionals interested in the field can also learn about becoming a polygraph examiner through our comprehensive resources.
Countermeasures and the Robustness of the Comparison Principle
Research on Countermeasure Effectiveness
The integrity of the Either-Or Rule's binary comparison model depends on the assumption that physiological responses genuinely reflect the examinee's psychological set rather than deliberate manipulation. Research by Honts, Raskin, and Kircher (1994) examined the effects of both physical and mental countermeasures on the comparison question polygraph test in a laboratory experiment with 120 participants recruited from the general community [20]Verified Mental and Physical Countermeasures Reduce the Accuracy of Polygraph Tests
Found trained physical and mental countermeasures each enabled approximately 50% of guilty subjects to defeat the polygraph test in a laboratory experiment with 120 participants. The study found that trained countermeasures enabled approximately 50% of guilty subjects to defeat the test [20]Verified Mental and Physical Countermeasures Reduce the Accuracy of Polygraph Tests
Found trained physical and mental countermeasures each enabled approximately 50% of guilty subjects to defeat the polygraph test in a laboratory experiment with 120 participants.
However, important context is needed to interpret these findings constructively. As Honts (2014) noted in the Credibility Assessment volume, the spontaneous use of countermeasures — attempts by untrained individuals to defeat the polygraph — is generally ineffective for guilty subjects and may actually reduce accuracy for innocent examinees [20]Verified Mental and Physical Countermeasures Reduce the Accuracy of Polygraph Tests
Found trained physical and mental countermeasures each enabled approximately 50% of guilty subjects to defeat the polygraph test in a laboratory experiment with 120 participants. The distinction between trained and spontaneous countermeasures is critical: the laboratory findings involved specific coaching on precisely timed physical or mental techniques, a scenario that is far less common in operational settings.
Modern polygraph systems incorporate activity sensors that monitor for physical countermeasure attempts, and trained examiners are skilled at recognizing anomalous physiological patterns. The OSS-3 algorithm includes a test of proportions designed to help discriminate between countermeasures and random artifacts [16]Verified Brute-Force Comparison: A Monte Carlo Study of the Objective Scoring System version 3 (OSS-3) and Human Polygraph Scorers
Describes the OSS-3 scoring algorithm and validates its performance against human polygraph scorers using brute-force statistical methods. Additionally, proper pretest interview techniques and the establishment of strong examiner-examinee rapport serve as important procedural safeguards.
The published literature on countermeasures can be summarized as follows: although members of the public may believe the polygraph is easy to defeat, studies show otherwise; the polygraph continues to discriminate deception and truth-telling at rates significantly greater than chance despite the countermeasure challenge [16]Verified Brute-Force Comparison: A Monte Carlo Study of the Objective Scoring System version 3 (OSS-3) and Human Polygraph Scorers
Describes the OSS-3 scoring algorithm and validates its performance against human polygraph scorers using brute-force statistical methods. For more on how mental state affects testing, explore our guides on hypnosis and polygraph testing and polygraph considerations for individuals with borderline personality disorder or bipolar disorder.
Frequently Asked Questions
What is Backster's Either-Or Rule in polygraph testing?
The Either-Or Rule (EOR) is a scoring principle developed by Cleve Backster circa 1960 that states an examinee's physiological responses will be predominantly stronger to either the relevant questions or the comparison questions during a polygraph examination. This creates a binary pattern: if responses are stronger to relevant questions, deception is indicated; if stronger to comparison questions, truthfulness is indicated. The EOR permits scoring relevant question tracings against a stronger bracketing comparison tracing only [5]Verified A Comparison of the Backster Scoring and Traditional Federal Scoring Using Computerized Analysis
Confirms Backster was the first to apply a positive and negative scoring system comparing relevant against comparison questions, and documents the EOR versus Federal scoring methods.
How accurate is the Either-Or Rule according to research?
Research by Meiron, Krapohl, and Ashkenazi (2008) found that applying the EOR increased correct decisions from 70% to 80% and reduced inconclusive outcomes from 27% to 17% [8]Verified An Assessment of the Backster 'Either-Or' Rule in Polygraph Scoring
Empirically tested Backster's EOR using 100 field cases; found EOR increased correct decisions from 70% to 80% and reduced inconclusives from 27% to 17%. All improvement was attributable to better detection of deceptive cases. Meanwhile, the 2011 APA Meta-Analytic Survey found that validated polygraph techniques overall produced 87% decision accuracy (CI 80%–94%) [2]Verified Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms aggregated accuracy of 87% (CI 80%–94%) for validated polygraph techniques across 38 studies and 3,723 examinations. Matte's 2010 field study found the EOR produced the fewest inconclusives and no errors when relevant questions elicited strong responses [6]Verified A Field Study of the Backster Zone Comparison Technique's Either-Or Rule and Scoring System Versus Two Other Scoring Systems When Relevant Question Elicits Strong Response
Analyzed the comparative effectiveness of the Backster Either-Or Rule versus Federal and Matte Quadri-Track scoring systems, finding EOR produced fewest inconclusives with no errors when relevant questions elicited strong responses.
What is the difference between Backster scoring and Federal scoring?
The key difference lies in how comparison questions are selected for scoring. The Backster You-Phase uses the EOR to select the bracketing comparison tracing to score against, permitting scoring only against a stronger comparison question [5]Verified A Comparison of the Backster Scoring and Traditional Federal Scoring Using Computerized Analysis
Confirms Backster was the first to apply a positive and negative scoring system comparing relevant against comparison questions, and documents the EOR versus Federal scoring methods. The Federal You-Phase system always scores relevant question tracings against the stronger bracketing comparison question regardless of the Either-Or principle [5]Verified A Comparison of the Backster Scoring and Traditional Federal Scoring Using Computerized Analysis
Confirms Backster was the first to apply a positive and negative scoring system comparing relevant against comparison questions, and documents the EOR versus Federal scoring methods. Research has compared these systems, with studies such as Dollins (2003) finding the Backster system produced larger negative values while showing no meaningful difference in false positive rates [9]Verified Relative Efficacy of the Utah, Backster, and Federal Scoring Rules: A Preliminary Investigation
Found Backster scoring produced larger negative values and imbalance in conclusive scores compared to Utah and Federal systems, with no meaningful difference in false positive rates.
What is Psychological Set theory and how does it relate to the Either-Or Rule?
Psychological Set is the theoretical framework underlying the Either-Or Rule. It posits that during a polygraph examination, an examinee's attention and emotional concern will be directed primarily toward whichever category of questions poses the greatest perceived threat to their well-being [6]Verified A Field Study of the Backster Zone Comparison Technique's Either-Or Rule and Scoring System Versus Two Other Scoring Systems When Relevant Question Elicits Strong Response
Analyzed the comparative effectiveness of the Backster Either-Or Rule versus Federal and Matte Quadri-Track scoring systems, finding EOR produced fewest inconclusives with no errors when relevant questions elicited strong responses. For deceptive individuals, relevant questions pose the greatest threat; for truthful individuals, comparison questions provoke greater concern. The EOR formalizes this observation into a scoring methodology.
What polygraph techniques are based on the Either-Or Rule?
The Backster Zone Comparison Technique is the original technique incorporating the EOR. From it, several derivative techniques have emerged, including the Federal Zone Comparison Technique (used by U.S. government agencies), the Matte Quadri-Track Zone Comparison Technique, and the Utah Zone Comparison Technique [4]Verified Psychological Structure and Theoretical Concept of the Backster Zone Comparison Technique and the Quadri-Track Zone Comparison Technique
Confirms the theoretical concept and psychological structure of the Backster Zone Comparison Technique and its relationship to derivative techniques. Each of these techniques employs the fundamental comparison principle that Backster formalized, though they differ in specific scoring rules and question selection methods.
How has computerized scoring affected the Either-Or Rule?
Modern computerized scoring systems like the OSS-3 (Objective Scoring System Version 3) and the Empirical Scoring System (ESS) have digitized the comparison principle underlying the EOR [16]Verified Brute-Force Comparison: A Monte Carlo Study of the Objective Scoring System version 3 (OSS-3) and Human Polygraph Scorers
Describes the OSS-3 scoring algorithm and validates its performance against human polygraph scorers using brute-force statistical methods. These algorithms use measurements of physiological features to produce objective, probabilistic assessments. The OSS-3 eliminates subjectivity in chart interpretation and has been validated across multiple research samples. The CPS (Computerized Polygraph System) developed at the University of Utah was the world's first fully automated system and remains in worldwide use [17]Verified Computerized Polygraph System (CPS)
Confirms the CPS as the world's first fully automated polygraph system developed by Raskin and Kircher at the University of Utah, now in its fourth generation.
How many hours of training are required to become a polygraph examiner?
APA-accredited basic polygraph examiner courses require a minimum of 400 hours of instruction [19]Verified Basic Polygraph Examiner Course — PEAK CATC
Confirms APA-accredited basic polygraph examiner courses require a minimum of 400 hours of instruction. These programs cover physiological measurement principles, validated testing techniques including the Zone Comparison methods, question construction, pretest interview procedures, both manual and computerized scoring systems, ethics, legal considerations, and extensive supervised practice. Students must also complete practical examinations and submit field cases following graduation.
Can countermeasures defeat the comparison question polygraph test?
Research by Honts, Raskin, and Kircher (1994) found that specifically trained countermeasures could enable approximately 50% of guilty subjects to defeat the test in laboratory conditions [20]Verified Mental and Physical Countermeasures Reduce the Accuracy of Polygraph Tests
Found trained physical and mental countermeasures each enabled approximately 50% of guilty subjects to defeat the polygraph test in a laboratory experiment with 120 participants. However, spontaneous (untrained) countermeasure attempts are generally ineffective for guilty subjects [20]Verified Mental and Physical Countermeasures Reduce the Accuracy of Polygraph Tests
Found trained physical and mental countermeasures each enabled approximately 50% of guilty subjects to defeat the polygraph test in a laboratory experiment with 120 participants. Modern polygraph systems incorporate activity sensors to detect physical countermeasures, and computerized algorithms like OSS-3 include tools to help identify anomalous response patterns [16]Verified Brute-Force Comparison: A Monte Carlo Study of the Objective Scoring System version 3 (OSS-3) and Human Polygraph Scorers
Describes the OSS-3 scoring algorithm and validates its performance against human polygraph scorers using brute-force statistical methods. Proper examiner training and pretest procedures also serve as important safeguards against countermeasure attempts.
Sources & References
Documents the evolution from subjective to objective decision criteria in polygraph testing and their impact on reliability and accuracy
Confirms aggregated accuracy of 87% (CI 80%–94%) for validated polygraph techniques across 38 studies and 3,723 examinations
Confirms Backster's biographical details (1924–2013), CIA background, founding of the Backster School of Lie Detection, and development of the Zone Comparison Technique
Confirms the theoretical concept and psychological structure of the Backster Zone Comparison Technique and its relationship to derivative techniques
Confirms Backster was the first to apply a positive and negative scoring system comparing relevant against comparison questions, and documents the EOR versus Federal scoring methods
Analyzed the comparative effectiveness of the Backster Either-Or Rule versus Federal and Matte Quadri-Track scoring systems, finding EOR produced fewest inconclusives with no errors when relevant questions elicited strong responses
Confirms the 1963 publication as the first highly standardized rationale and structure for the administration and scoring of a comparison question technique
Empirically tested Backster's EOR using 100 field cases; found EOR increased correct decisions from 70% to 80% and reduced inconclusives from 27% to 17%
Found Backster scoring produced larger negative values and imbalance in conclusive scores compared to Utah and Federal systems, with no meaningful difference in false positive rates
The Two-Stage Rule successfully reduced inconclusive polygraph results while maintaining classification accuracy equivalent to the Grand Total Rule alone
Identified optimal cutscores and two-stage decision rules that maximized accuracy while minimizing inconclusive rates for the MGQT format
Confirms the comparison question technique was first developed in 1947 and describes the CQT methodology comparing different question types
Comprehensive reference on credibility assessment methods including polygraph techniques, computerized systems, and countermeasure research
Meta-analysis of 138 datasets confirming that prior CQT reviews generally produced overall accuracy estimates of over 85%, with motivation showing positive linear relationship with accuracy
Found no significant differences in accuracy between DoDPI and Utah scorers when decision rules, chart number, and data channels were equated
Describes the OSS-3 scoring algorithm and validates its performance against human polygraph scorers using brute-force statistical methods
Confirms the CPS as the world's first fully automated polygraph system developed by Raskin and Kircher at the University of Utah, now in its fourth generation
Weighted EDA scores alone reduced inconclusive results by 49%, while combining EDA weighting with multinomial cut-scores achieved a 72% reduction
Confirms APA-accredited basic polygraph examiner courses require a minimum of 400 hours of instruction
Found trained physical and mental countermeasures each enabled approximately 50% of guilty subjects to defeat the polygraph test in a laboratory experiment with 120 participants
Established decision rules specifically for evidentiary-quality polygraph examinations with more conservative cutscores to minimize errors in legal contexts
Foundational research relevant to understanding communication in polygraph contexts — the 7/38/55 ratio applies only to judgments of emotional attitude, not to deception detection
Provides foundational analysis of the CQT and its physiological measurement basis including the role of differential anxiety and fear responses
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