Terminology Reference for the Science of Psychophysiological Detection

The fourth edition of the Terminology Reference for the Science of Psychophysiological Detection of Deception provides comprehensive definitions for approximately 550 terms in the polygraph field, updated to reflect the transition to evidence-based practices and digital instrumentation. This scholarly compilation bridges polygraph terminology with mainstream scientific concepts across psychology, neuroscience, and forensic science disciplines.

The authors systematically compiled and updated approximately 550 alphabetically-listed definitions through comprehensive literature review, added new terms reflecting emerging technologies, removed outdated concepts, and included images to enhance understanding.

This fourth edition represents a 25-year evolution of polygraph terminology standardization, capturing the field's transformation to digital instrumentation and evidence-based practices. The authors systematically reviewed literature, consulted experts, and updated definitions to align with current scientific understanding. The reference contains approximately 550 alphabetically-listed terms with contextualized definitions that bridge polygraph concepts with mainstream psychophysiological and behavioral sciences. Key areas include directed-lie comparison questions, standardized algorithms, and arousal theory, with outdated concepts removed and emerging validated technologies added.

This standardized terminology reference facilitates international communication among polygraph researchers, practitioners, legal professionals, and policymakers, while supporting the field's continued evolution toward evidence-based practices and scientific credibility.

Background & Context

The fourth edition of the Terminology Reference for the Science of Psychophysiological Detection of Deception represents a comprehensive update to a foundational resource first published 25 years ago, capturing dramatic transformations in the polygraph field including the complete transition from analog to digital instrumentation, the shift from authority-based to evidence-based practices, and the mainstreaming of concepts and terminology. This reference work serves a critical function in the polygraph profession, bridging the gap between specialized polygraph terminology and established concepts in sister scientific disciplines.

The reference guide is specifically designed to indicate to scientists and others outside the polygraph profession how polygraph concepts relate to mainstream concepts in related disciplines. This standardization effort addresses a longstanding challenge in credibility assessment: the need for common language and definitions that enable effective communication among researchers, practitioners, legal professionals, and policymakers across international boundaries.

The authors dedicated this fourth edition to the memory of Shirley Sturm, who passed in 2020 and was the first woman President of the American Polygraph Association, described as a teacher, coveted mentor, and fiercely independent thinker. This acknowledgment underscores the collaborative, evolving nature of polygraph science and the importance of institutional memory in maintaining professional standards.

Research Design & Methodology

Rather than a traditional empirical study, this work represents a systematic scholarly compilation and definitional project. The reference contains approximately 550 terms listed alphabetically with definitions, each carefully contextualized within the broader psychophysiological and behavioral science literature.

The authors updated references, added new terms, removed others, and included images for some terms to help readers understand them better. The methodology involved comprehensive literature review, consultation with subject matter experts, and alignment with current evidence-based practices. Key elements of the compilation approach include:

• Systematic review of terminology across historical polygraph literature
• Integration of contemporary neuroscience and psychophysiology terminology
• Removal of outdated or discredited concepts
• Addition of emerging technologies and techniques validated since the previous edition

The edition updates research citations and adds new terms relevant to the current scientific status of polygraphy, with definitions from previous editions revised to take into account more recent findings and events. This iterative refinement process ensures the reference remains aligned with evolving scientific understanding.

Results & Key Findings

Comprehensive standardization of polygraph terminology represents the primary outcome of this scholarly work. The reference provides authoritative definitions for the full spectrum of psychophysiological detection concepts, from fundamental physiological mechanisms to specific testing protocols and scoring methodologies.

Key conceptual areas covered in the terminology reference include:

• Directed-lie comparison (DLC) questions, which differ from probable-lie comparison questions in that examinees are instructed to answer untruthfully, with advantages including easier standardization, less intrusiveness, and reduced dependence on examiner skill
• Algorithms defined as systems of standardized steps or decision rules that analyze physiologic data from structured examinations to estimate likelihood of deception or assess which questions elicited the greatest response
• Arousal theory, which holds that stimuli have different intrinsic cognitive and/or emotional arousal potential for each subject, with discrimination achieved by assessing which stimuli draw the most responsivity
• Three types of arousal proposed by Lacey: behavioral (observed in outward responses), autonomic (measured by psychophysiological changes in the peripheral nervous system), and cortical (measured as EEG desynchronization and fast waves)

The reference includes 94 references and 8 informational websites, providing practitioners and researchers with a robust foundation for understanding contemporary polygraph science. This extensive citation network connects polygraph-specific concepts to peer-reviewed research in psychology, neuroscience, and forensic science.

Discussion & Significance

This terminology reference represents a foundational contribution to professionalizing and standardizing the polygraph field. By providing authoritative definitions grounded in scientific literature, it addresses a critical need for common language that has historically hindered communication between polygraph practitioners and the broader scientific community. The work's significance extends beyond simple definition to conceptual clarification that can reduce misunderstandings about what polygraph testing can and cannot accomplish.

The timing of this fourth edition is particularly significant given ongoing debates about credibility assessment technologies. The authors note that despite predictions of the demise of the polygraph, the profession has accomplished the shift from authority-based to evidence-based practices. This standardized terminology supports that transition by ensuring that empirical research uses consistent operational definitions, enabling meaningful comparison across studies and meta-analyses.

The British Polygraph Society adapted this American Polygraph Association reference as the foundation for their own terminology guide, subsequently revising and expanding it to reflect UK standards, practices, and advancements in polygraph science. This international adoption demonstrates the reference's value as a starting point for standardization efforts across different jurisdictions and regulatory environments.

Limitations & Considerations

As a definitional reference rather than an empirical study, this work does not itself generate new scientific evidence about polygraph validity or effectiveness. The quality and utility of the definitions depend on the underlying research cited, which varies in methodological rigor across different concepts and techniques. Some definitions reflect consensus among practitioners that may not yet have robust empirical validation.

The information published in the Terminology Reference does not necessarily reflect the position of the American Polygraph Association, indicating that the definitions represent the authors' scholarly synthesis rather than official organizational policy. Users should recognize that terminology standardization is an ongoing process, and definitions may continue to evolve as new research emerges and scientific understanding advances.

Practical Applications

For polygraph examiners, this reference provides essential guidance on proper terminology usage in reports, testimony, and professional communication. Standardized definitions reduce ambiguity in describing test procedures, physiological responses, and decision outcomes. For consumers of polygraph services—including law enforcement agencies, attorneys, and employers—the reference offers crucial context for understanding what examiners mean when using technical terminology, enabling more informed evaluation of polygraph results.

The reference also serves educational functions, providing students in polygraph training programs with authoritative definitions that align with evidence-based practices. By grounding terminology in peer-reviewed scientific literature from psychology, neuroscience, and forensic science, the work helps integrate polygraph practice into the broader credibility assessment and behavioral science communities. Researchers benefit from standardized operational definitions that facilitate replication and meta-analysis across studies conducted in different laboratories and field settings.