Japan built its testing around the Concealed Information Test, and NRIPS standardized an approach to the lie detector test quite different from the American model.
Japan stands alone among industrialized nations in using the Concealed Information Test as its exclusive polygraph method in criminal investigations. Researchers at the National Research Institute of Police Science (NRIPS) — including Izumi Matsuda, Tokihiro Ogawa, Michiko Tsuneoka, and Akemi Osugi — have spent decades standardizing and refining CIT protocols used by approximately 100 examiners conducting 5,000 tests annually across all 47 prefectures. Their work has provided the international scientific community with invaluable field data and helped establish the CIT as one of the most scientifically grounded polygraph methods available.
TL;DR — The Short Version
- Japan is the only country that exclusively uses the Concealed Information Test (CIT) rather than the Comparison Question Test (CQT) for all polygraph examinations in criminal investigations.
- The National Research Institute of Police Science (NRIPS), located in Kashiwa, Chiba Prefecture, serves as the central hub for CIT research, methodology development, and examiner training across all 47 prefectures.
- Key NRIPS researchers — Izumi Matsuda, Tokihiro Ogawa, and Michiko Tsuneoka — along with former examiner Akemi Osugi, have published extensively on CIT methodology and statistical scoring in leading international journals.
- Approximately 100 trained examiners conduct about 5,000 CIT examinations annually in Japan, with examiners required to complete a 3-month intensive training course at the Training Center of Forensic Science.
- Meta-analyses of CIT research demonstrate strong validity with mean correct detection rates of 78–86% for guilty subjects and 94–99% for innocent subjects, with false positive rates averaging just 4.1%.
- Japan's Supreme Court accepted polygraph CIT results as admissible evidence beginning in 1968, and the system has been in continuous use for criminal investigations for over 50 years.
Who This Guide Is For
- Polygraph examiners interested in CIT methodology and alternative testing paradigms
- Forensic psychology and psychophysiology students studying scientifically grounded lie detection methods
- Researchers looking for the history and evidence base behind the Concealed Information Test
- Legal professionals exploring the scientific foundations of different polygraph techniques
- Law enforcement officials curious about Japan's centralized and standardized polygraph model
- Anyone interested in how international polygraph practices compare across countries
Japan's Unique Polygraph System
The Only Country Using CIT Exclusively
Japan is the only country in the world where the Concealed Information Test (CIT) is widely and exclusively applied to criminal investigations [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate. The Comparison Question Test (CQT), which dominates polygraph practice in the United States, Canada, Israel, and most of the Western world, is not used at all in Japanese law enforcement [2]Verified The Comparison Question Test versus the Concealed Information Test? That was the question in Japan
Confirms Japanese law enforcement uses only the CIT for memory detection in real-life criminal investigations and the CQT is not used. This remarkable divergence makes Japan the world's primary real-world testing ground for CIT-based polygraph methodology, providing invaluable field data that laboratory research alone cannot produce.
The CIT — originally called the Guilty Knowledge Test (GKT) — was first introduced by Dr. David Lykken in 1959 [3]Verified Memory detection with the Concealed Information Test: A meta analysis of skin conductance, respiration, heart rate, and P300 data
Confirms CIT effect sizes: d = 1.55 for SCR, d = 1.11 for RLL, d = 0.89 for HR, and d = 1.89 for P300. While Lykken's ideas were largely set aside by American polygraph practitioners committed to the CQT, Japanese forensic scientists recognized that the CIT's information-detection framework was more scientifically testable and more compatible with Japan's legal and cultural environment. The result is a national polygraph program that many psychophysiologists regard as the most scientifically defensible in the world.
The NRIPS: Japan's Central Polygraph Research Hub
Japan's polygraph system is administered through the National Police Agency (NPA), which oversees law enforcement across all 47 prefectures. The NPA's National Research Institute of Police Science (NRIPS), located in Kashiwa, Chiba Prefecture, serves as the central hub for polygraph research, methodology development, and examiner training [4]Verified NRIPS Organization
Confirms NRIPS organizational structure with Fourth Department of Forensic Science responsible for polygraph examination. The NRIPS First Information Science Section is specifically responsible for application of psychology and cognitive neuroscience to criminal investigations, with polygraph examination as its primary research focus [5]Verified NRIPS First Information Science Section
Confirms NRIPS polygraph research focus, portable digital polygraph system with 20+ channels, and cardiovascular response research.
This centralized structure is unusual by international standards. In the United States, for example, polygraph practice is fragmented across federal agencies, state agencies, private practitioners, and multiple competing professional organizations — each with different standards and preferred techniques. For those curious about the American landscape, our guide on choosing a polygraph examiner explains these varying standards. Japan's centralized model ensures uniform practice and quality control across the entire nation.
The NRIPS employs trained forensic psychologists and psychophysiologists — not just technicians — to conduct and oversee polygraph research. This meant that from the very beginning, Japan's polygraph system was shaped by scientists whose primary concern was empirical validity. Key researchers at NRIPS who have driven CIT standardization include Izumi Matsuda, Tokihiro Ogawa, and Michiko Tsuneoka [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate, along with earlier contributors like Akemi Osugi, who served as a polygraph examiner with Japanese police for over ten years before becoming an associate professor of investigative psychology at Fukuyama University [6]Verified Daily application of the Concealed Information Test: Japan
Provides definitive description of how CIT is practiced daily in Japanese criminal investigations with approximately 5,000 annual examinations and ~100 examiners.
Historical Roots: From the 1950s to Today
The historical roots of Japan's CIT preference trace back to the early 1950s. The Keeler model 302 polygraph was first introduced to Japan in 1953 and served as a pattern for two domestically produced polygraphs introduced in 1955: the YKK polygraph and the TKK polygraph [7]Verified Psychophysiological Deception in Japan: The Past and the Present
Confirms Keeler model 302 was introduced to Japan in 1953, YKK and TKK polygraphs developed in 1955, and examiner training at NRIPS since 1953. Since 1953, police officers and technical officers have been trained as polygraph examiners at what is now the NRIPS [7]Verified Psychophysiological Deception in Japan: The Past and the Present
Confirms Keeler model 302 was introduced to Japan in 1953, YKK and TKK polygraphs developed in 1955, and examiner training at NRIPS since 1953. For context on the evolution of early polygraph instruments, Keeler's design was a breakthrough that enabled widespread adoption.
Japan's polygraph system has grown substantially since those early days. By the 1990s, more than 5,000 polygraphic examinations were being administered annually by Japanese police agencies [8]Verified Development of the Polygraph Technique in Japan for Detection of Deception
Confirms more than 5,000 polygraph examinations per year in Japan with approximately 90% accuracy rate. The well-controlled polygraph technique achieved an accuracy rate of approximately 90% for diagnoses, providing both reasonable validity and reliability [8]Verified Development of the Polygraph Technique in Japan for Detection of Deception
Confirms more than 5,000 polygraph examinations per year in Japan with approximately 90% accuracy rate. Today, the Japanese Supreme Court has accepted polygraph results as admissible evidence since 1968 [9]Verified Broadening the Use of the Concealed Information Test in the Field (Full Text)
Confirms Supreme Court admitted polygraph results as evidence in 1968, describes CIT field procedures, and details searching CIT methodology, and CIT results continue to be discussed in court proceedings.
Several cultural and legal factors contributed to Japan's embrace of the CIT. Japan's criminal justice system emphasizes cooperation rather than adversarial confrontation. The CIT's non-accusatory format — presenting multiple-choice items and measuring which one triggers recognition — fit naturally within this system. Japanese legal standards also placed high value on the scientific basis of forensic evidence, creating demand for a polygraph method whose theoretical foundations could withstand academic scrutiny. The centralized NPA structure meant that once the CIT was adopted, it could be implemented uniformly across the entire national police system.
CIT vs. CQT: Two Fundamentally Different Approaches
Information Detection vs. Deception Detection
Understanding the core differences between the CIT and the CQT is essential to appreciating Japan's approach. The CQT, used in most of the world, is a deception detection technique. It asks direct accusatory questions and compares physiological responses against responses to broader comparison questions. For a full breakdown of how different polygraph test formats work, see our comparison guide.
The CIT takes a completely different approach — it is an information detection technique that aims to detect crime-relevant memory rather than deception itself [2]Verified The Comparison Question Test versus the Concealed Information Test? That was the question in Japan
Confirms Japanese law enforcement uses only the CIT for memory detection in real-life criminal investigations and the CQT is not used. In the CIT, the examiner presents multiple-choice items where only one is relevant to the crime. For example, the question 'What was the murder weapon?' could be paired with answers such as 'gun,' 'knife,' 'hammer,' 'rope,' or 'bat' — typically five or more plausible answers, of which only one is correct [9]Verified Broadening the Use of the Concealed Information Test in the Field (Full Text)
Confirms Supreme Court admitted polygraph results as evidence in 1968, describes CIT field procedures, and details searching CIT methodology. The theory holds that a guilty person who recognizes the correct item will produce an involuntary orienting response — a measurable autonomic reaction — while an innocent person will respond equally to all items.
In Japan, when an examinee recognizes the relevant item, the relevant item elicits greater skin conductance, slower heart rate, depressed respiration, and smaller normalized pulse volume than the irrelevant items [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate. This multi-channel response pattern provides robust and reliable differentiation between knowledgeable and unknowledgeable examinees. To understand how a polygraph works at a technical level, see our detailed guide.
Why Academic Psychophysiologists Favor the CIT
Academic psychophysiologists have long been more supportive of the CIT than the CQT. A landmark survey by Iacono and Lykken found that 77% of Society for Psychophysiological Research members and 72% of American Psychological Association Division 1 members believed the CIT to be based on scientifically sound psychological principles [10]Verified A review of the polygraph: history, methodology and current status
Confirms Iacono and Lykken survey results: 77% SPR and 72% APA Division 1 support for CIT, vs. 36% and 30% for CQT. In comparison, only 36% and 30% respectively believed the same about the CQT [10]Verified A review of the polygraph: history, methodology and current status
Confirms Iacono and Lykken survey results: 77% SPR and 72% APA Division 1 support for CIT, vs. 36% and 30% for CQT. This strong academic endorsement reflects the CIT's grounding in well-established cognitive science principles.
The 2003 National Academy of Sciences report on polygraph testing also noted the CIT's stronger theoretical foundation compared to the CQT [11]Verified The Polygraph and Lie Detection
The National Academy of Sciences comprehensive review of polygraph research including CIT and CQT methodologies. Researchers like Gershon Ben-Shakhar at the Hebrew University of Jerusalem, Eitan Elaad in Israel, Ewout Meijer at Maastricht University, and Bruno Verschuere at the University of Amsterdam have all contributed substantially to CIT research. Their work, combined with the field data from Japan, has built a compelling evidence base for the CIT as a forensic tool.
How NRIPS Standardized the CIT Across Japan
Examiner Training and Certification
Standardization begins with training. All Japanese polygraph examiners must complete a 3-month intensive training course at the Training Center of Forensic Science, affiliated with the NRIPS [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate. Examiner trainees are selected from university graduates majoring in psychology or other related technical fields [7]Verified Psychophysiological Deception in Japan: The Past and the Present
Confirms Keeler model 302 was introduced to Japan in 1953, YKK and TKK polygraphs developed in 1955, and examiner training at NRIPS since 1953. In the basic training course, they first learn fundamental knowledge of psychophysiology, statistics, and other related fields, then learn CIT principles, how to create CIT questions, and how to measure and analyze psychophysiological indices [12]Verified Applications of Legal Psychology in Japan: Current Practice, Research Knowledge, and Future Directions
Confirms CIT training procedures at NRIPS, 3-month training course requirements, and describes CIT field practice in Japan. Without the certificate from this course, they cannot conduct the CIT in the field.
Approximately 100 examiners serve across Japan's 47 prefectures [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate. All examiners are assigned to a forensic science laboratory of a prefectural police headquarters. The laboratory staff consists not of police officers but of technical officers who are also engaged in research [6]Verified Daily application of the Concealed Information Test: Japan
Provides definitive description of how CIT is practiced daily in Japanese criminal investigations with approximately 5,000 annual examinations and ~100 examiners — a critical distinction that ensures scientific rigor. This centralized training model stands in stark contrast to the fragmented training landscape seen in countries like the United States, where different schools teach different techniques with varying standards. For those interested in pursuing a career in polygraph examination, our guide on how to become a polygraph examiner covers international pathways.
Standardized Question Construction
The standardized protocol establishes precise rules for how CIT questions must be built. Each question set requires one relevant item (known only to the perpetrator and investigators) presented among several neutral alternatives — typically five or more plausible answers. The alternatives must be equally plausible to an innocent person, and the relevant item must not be distinguishable through media exposure or common knowledge.
Japan's law enforcement agencies maintain greater control over crime scenes and what information regarding crime is made public than most Western countries, which is part of the reason why the CIT can be used on the scale that it is [9]Verified Broadening the Use of the Concealed Information Test in the Field (Full Text)
Confirms Supreme Court admitted polygraph results as evidence in 1968, describes CIT field procedures, and details searching CIT methodology. When a CIT examination is ordered, the forensic examiner works closely with the investigating officers to identify crime-relevant details that only the perpetrator would know: the specific weapon used, the exact location of a hidden item, the amount of money stolen, or the time of the crime. These construction standards address one of the CIT's biggest practical challenges: ensuring that crime-specific details remain truly concealed.
Physiological Measurement Protocols
The standardized protocol specifies which physiological channels must be recorded during CIT examinations. In Japan, the examiner usually records several physiological measures: electrocardiography (ECG), respiratory movement, skin conductance, and pulse wave [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate. Since 2005, Japan has used a portable digital polygraph system that simultaneously records these channels [13]Verified Development of a portable digital polygraph system
Confirms development of Japan's portable digital polygraph system in 2005. The latest system is capable of recording more than 20 channels of various physiological indices [5]Verified NRIPS First Information Science Section
Confirms NRIPS polygraph research focus, portable digital polygraph system with 20+ channels, and cardiovascular response research. For more on how long polygraph equipment lasts and the technology behind modern systems, see our equipment guide.
The NRIPS has also investigated the applicability of cardiovascular responses including blood pressure, peripheral skin blood flow, and normalized pulse volume to the polygraph examination [5]Verified NRIPS First Information Science Section
Confirms NRIPS polygraph research focus, portable digital polygraph system with 20+ channels, and cardiovascular response research. This ongoing research ensures that Japan's CIT system continues to evolve with advances in psychophysiological measurement technology.
Each CIT item is presented about three to five times in a question, and the order of presentation changes each time [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate. In addition, the examiner does not infer guilt or innocence by summarizing physiological responses for all questions, but infers recognition of individual questions by analyzing physiological responses to each question separately. This question-focused judgment approach is a distinctive feature of the Japanese CIT that differs from typical Western polygraph practice. For comparison with Western approaches, see our guide on how many chart runs a polygraph exam requires.
Scoring Methods: From Visual Inspection to Statistical Approaches
Traditionally, Japanese CIT results have been derived primarily through the examiner's visual inspection of physiological charts. The examiner ascertains whether the examinee showed differential responses based on the charts, the difference between the mean responses to crime-relevant and irrelevant items, and the consistency of the response differences across repetitions [9]Verified Broadening the Use of the Concealed Information Test in the Field (Full Text)
Confirms Supreme Court admitted polygraph results as evidence in 1968, describes CIT field procedures, and details searching CIT methodology. Visual inspection enables the examiner to flexibly adjust measures to consider the examinee's response tendency, but is sometimes regarded as subjective and dependent on the skill and experience of the examiner [9]Verified Broadening the Use of the Concealed Information Test in the Field (Full Text)
Confirms Supreme Court admitted polygraph results as evidence in 1968, describes CIT field procedures, and details searching CIT methodology.
However, NRIPS researchers have been at the forefront of developing more objective, statistical scoring methods. Izumi Matsuda and colleagues have proposed statistical discrimination methods that can be easily applied to CIT interpretation in the field [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate. These include effect size calculations, randomization tests, and multivariate approaches that combine data from multiple physiological channels. Introducing statistical judgment methods enhances objectivity and the probative power of CIT results in court [9]Verified Broadening the Use of the Concealed Information Test in the Field (Full Text)
Confirms Supreme Court admitted polygraph results as evidence in 1968, describes CIT field procedures, and details searching CIT methodology.
Matsuda's work on latent class discrimination methods and dynamic mixture distributions represented further innovations in within-individual classification [14]Verified A new discrimination method for the Concealed Information Test using pretest data and within-individual comparisons
Confirms Matsuda's latent class discrimination method and within-individual CIT classification innovations. This evolution from subjective to objective scoring reflects a broader trend in polygraph science. In the United States, researchers like Raymond Nelson, Mark Handler, and Donald Krapohl developed the Objective Scoring System (OSS) and Empirical Scoring System (ESS) to achieve similar goals of standardization and objectivity [15]Verified Development of the Objective Scoring System (OSS) and Empirical Scoring System (ESS)
Developed and validated OSS and ESS computerized scoring methods, replacing subjective hand-scoring. The OSS-3 algorithm demonstrated balanced sensitivity and specificity, outperforming 10 human scorers in validation studies [16]Verified Objective Scoring System, Version 3 (OSS-3): Development and Validation
OSS-3 demonstrated balanced sensitivity/specificity and outperformed 10 human scorers. Cross-cultural validation of the ESS achieved mean accuracy of 90.1% [17]Verified Empirical Scoring System: A Cross-Cultural Replication and Extension Study
International validation achieved mean accuracy of 90.1% demonstrating ESS validity across cultures, and the Utah Numerical Scoring System formalized by Bell, Raskin, Kircher, and Honts provided standardized procedures achieving the highest rates of criterion accuracy [18]Verified The Utah Numerical Scoring System
Formalized the Utah-CQT numerical scoring system achieving highest rates of criterion accuracy and inter-rater reliability.
CIT Accuracy: What the Evidence Shows
Meta-Analytic Evidence
The accuracy of the CIT has been evaluated through multiple comprehensive meta-analyses. Ben-Shakhar and Elaad's landmark 2003 meta-analysis covered 80 laboratory studies with 169 experimental conditions and a total of 5,198 participants, reporting an overall average effect size of d = 1.55 for skin conductance [19]Verified The Validity of Psychophysiological Detection of Information With the Guilty Knowledge Test: A Meta-Analytic Review
Confirms detection rates of 78-86% for guilty and 94-99% for innocent subjects, overall effect size of 1.55, and optimal conditions effect size of 3.12. Studies that best approximated real-world conditions produced an even more impressive average effect size of d = 3.12 [19]Verified The Validity of Psychophysiological Detection of Information With the Guilty Knowledge Test: A Meta-Analytic Review
Confirms detection rates of 78-86% for guilty and 94-99% for innocent subjects, overall effect size of 1.55, and optimal conditions effect size of 3.12. Vrij's reviews of GKT laboratory studies found mean correct detection rates of 78–86% for guilty subjects and 94–99% for innocent subjects [19]Verified The Validity of Psychophysiological Detection of Information With the Guilty Knowledge Test: A Meta-Analytic Review
Confirms detection rates of 78-86% for guilty and 94-99% for innocent subjects, overall effect size of 1.55, and optimal conditions effect size of 3.12.
Elaad's meta-analysis found that the weighted average false positive rate was just 4.1%, while the false negative rate was 19.4% [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate. This asymmetry — high detection rates combined with very low false positive rates — is one of the CIT's most attractive features from both a scientific and ethical standpoint. For more context on how false negatives affect polygraph testing, see our analysis.
The more recent 2014 meta-analysis by Meijer, Klein Selle, Elber, and Ben-Shakhar examined four physiological measures and found mean effect sizes of d = 1.55 for skin conductance, d = 1.11 for respiration line length, d = 0.89 for heart rate, and d = 1.89 for P300 event-related potentials [3]Verified Memory detection with the Concealed Information Test: A meta analysis of skin conductance, respiration, heart rate, and P300 data
Confirms CIT effect sizes: d = 1.55 for SCR, d = 1.11 for RLL, d = 0.89 for HR, and d = 1.89 for P300. These findings confirm that combining multiple physiological measures outperforms any single channel alone.
Japanese Field Data
Japan's field application of the CIT provides critical real-world validation data. With more than 5,000 polygraph examinations conducted each year since the 1970s, Japanese field data revealed an accuracy rate of approximately 90% for detecting deception [8]Verified Development of the Polygraph Technique in Japan for Detection of Deception
Confirms more than 5,000 polygraph examinations per year in Japan with approximately 90% accuracy rate. The CIT has been officially and systematically used in Japan for over 50 years, making it one of the longest-running standardized polygraph programs in the world.
Importantly, the response patterns observed in field CITs are consistent with those found in laboratory studies, supporting the external validity of CIT research. The consistency of these patterns across five decades of continuous application represents an extraordinary body of evidence rarely available in forensic psychology. As Osugi documented in her definitive chapter on daily CIT application in Japan, the system's long track record demonstrates that the CIT can be successfully implemented at scale when proper standardization and training are in place [6]Verified Daily application of the Concealed Information Test: Japan
Provides definitive description of how CIT is practiced daily in Japanese criminal investigations with approximately 5,000 annual examinations and ~100 examiners.
CIT in Japanese Police Work
How a Field CIT Examination Works
The field CIT process in Japan follows a structured flowchart developed and refined by NRIPS [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate. A consenting examinee receives the polygraph. At the beginning of the test, the examiner interviews the examinee to check what the examinee says about his or her knowledge of the crime. If the examinee says that he or she knows some crime details, the examiner will not perform CITs on these details [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate. This careful pre-test procedure ensures that only genuinely concealed information is tested.
The CIT is conducted in Japan for three primary purposes: (1) to reveal whether the examinee knows a specific criminal detail, (2) to obtain new crime-relevant information through the searching CIT, and (3) to reveal whether the examinee's statement is credible [9]Verified Broadening the Use of the Concealed Information Test in the Field (Full Text)
Confirms Supreme Court admitted polygraph results as evidence in 1968, describes CIT field procedures, and details searching CIT methodology. The searching CIT is a particularly innovative application unique to Japanese practice, where the crime-relevant item is not known to the examiner beforehand, allowing the CIT to uncover new investigative leads.
The results are rarely dealt with as primary evidence in court: only a few of the approximately 5,000 annual cases are discussed each year in judicial proceedings [9]Verified Broadening the Use of the Concealed Information Test in the Field (Full Text)
Confirms Supreme Court admitted polygraph results as evidence in 1968, describes CIT field procedures, and details searching CIT methodology. However, the Supreme Court admitted polygraph results as evidence in 1968, and recent legal literature has noted that the probative value of the CIT result can be relatively high when properly administered [9]Verified Broadening the Use of the Concealed Information Test in the Field (Full Text)
Confirms Supreme Court admitted polygraph results as evidence in 1968, describes CIT field procedures, and details searching CIT methodology.
The CIT as Memory Detection
A crucial distinction that Japanese practitioners emphasize is that the CIT does not aim to detect deception — rather, it aims to detect crime-relevant memory [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate. The CIT can assess whether an examinee knows details of a crime, despite saying 'I don't know.' The CIT can also reveal, through the examinee's memory, new crime-relevant information that the examiner and investigators did not previously know about [9]Verified Broadening the Use of the Concealed Information Test in the Field (Full Text)
Confirms Supreme Court admitted polygraph results as evidence in 1968, describes CIT field procedures, and details searching CIT methodology. Furthermore, the CIT can be used for assessing the credibility of examinees' statements.
This reframing of polygraph testing as memory detection rather than lie detection has profound implications for its scientific validity and legal defensibility. It shifts the focus from the inherently difficult question of whether someone is lying to the more empirically tractable question of whether someone recognizes specific information. To understand the broader context of polygraph limitations and capabilities, see our comprehensive guide.
Correct understanding of the CIT will change the role of the polygraph in criminal investigations worldwide. The development of statistical judgment methods will make the CIT more objective and promote its use outside Japan [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate. As Matsuda, Ogawa, and Tsuneoka have urged, the CIT has much potential, and Japan's decades of successful field application provide the blueprint for other countries to follow.
Key NRIPS Researchers and Their Contributions
Izumi Matsuda
Izumi Matsuda has been one of the most prolific CIT researchers at NRIPS. Based at the institute's Kashiwa campus, Matsuda has published extensively on statistical discrimination methods for CIT interpretation, physiological response patterns in the CIT, and the development of new measurement indices [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate. His 2006 study introduced a new discrimination method using pretest data and within-individual comparisons [14]Verified A new discrimination method for the Concealed Information Test using pretest data and within-individual comparisons
Confirms Matsuda's latent class discrimination method and within-individual CIT classification innovations, and his subsequent work on the latent class discrimination method and dynamic mixture distribution method represented significant advances in CIT scoring methodology.
Matsuda co-authored the landmark 2012 paper on the current and future status of the CIT for field use with Hiroshi Nittono and John J.B. Allen [20]Verified The Current and Future Status of the Concealed Information Test for Field Use
Describes current CIT field practice in Japan, statistical discrimination methods, and future research directions including EEG and P300, as well as the 2019 paper on broadening the use of the CIT in the field with Ogawa and Tsuneoka [1]Verified Broadening the Use of the Concealed Information Test in the Field
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate. His research has been instrumental in bridging the gap between Japanese field practice and international academic research. Matsuda now continues his CIT research at Aoyama Gakuin University.
Tokihiro Ogawa and Michiko Tsuneoka
Tokihiro Ogawa is a senior researcher at NRIPS who has contributed substantially to CIT methodology and accuracy research. Ogawa led a laboratory study assessing the accuracy of the CIT as a memory detection technique using a mock-theft paradigm, finding sensitivity of 83% and specificity of 91% [21]Verified Accuracy of concealed information test as a memory detection technique
Reports CIT sensitivity of 83% and specificity of 91% in mock-theft experiment. His 2015 paper with Matsuda and Tsuneoka was instrumental in clarifying the fundamental differences between CIT and CQT methodology [2]Verified The Comparison Question Test versus the Concealed Information Test? That was the question in Japan
Confirms Japanese law enforcement uses only the CIT for memory detection in real-life criminal investigations and the CQT is not used.
Michiko Tsuneoka, also at NRIPS, has co-authored key publications on broadening the use of the CIT and has contributed to research on pupil diameter responses and implicit association measures for forensic science applications [22]Verified KAKEN Researcher Profile: Tsuneoka Michiko
Confirms Michiko Tsuneoka's affiliation with NRIPS Fourth Department as senior researcher working on concealed information test. Together, these three researchers represent the current generation of NRIPS scientists continuing Japan's tradition of CIT excellence.
Akemi Osugi: From Field Examiner to Academic Researcher
Akemi Osugi, Ph.D., served as a polygraph examiner with the Japanese police for over ten years, conducting CIT examinations in actual criminal investigations [6]Verified Daily application of the Concealed Information Test: Japan
Provides definitive description of how CIT is practiced daily in Japanese criminal investigations with approximately 5,000 annual examinations and ~100 examiners. She completed her doctorate in psychology from Nagoya University while working as a polygraph examiner and spent eleven years working with the Japanese police force [23]Verified Akemi Osugi - Investigative Psychology Lab
Confirms Osugi was a CIT polygraph examiner for over ten years with Japanese police, now associate professor at Fukuyama University. Osugi authored the definitive chapter on daily application of the CIT in Japan for the Cambridge University Press volume 'Memory Detection: Theory and Application of the Concealed Information Test' (2011) [6]Verified Daily application of the Concealed Information Test: Japan
Provides definitive description of how CIT is practiced daily in Japanese criminal investigations with approximately 5,000 annual examinations and ~100 examiners.
Now an associate professor of investigative psychology at Fukuyama University, Osugi continues to research the relationship between P300-based CIT and emotional arousal, bridging the gap between autonomic and brain-based measures of concealed information [23]Verified Akemi Osugi - Investigative Psychology Lab
Confirms Osugi was a CIT polygraph examiner for over ten years with Japanese police, now associate professor at Fukuyama University. In 2025, she presented on Japanese CIT practice at the International Polygraph Conference in Hungary [24]Verified Akemi Osugi - Researchmap Profile
Confirms Osugi's 2025 presentation on Japanese CIT at International Polygraph Conference in Hungary and P300-CIT research, demonstrating her ongoing commitment to sharing Japan's CIT expertise with the global community.
Historical Foundations of the CIT
From Early Word Association to Modern CIT
The theoretical roots of the CIT extend back to early psychological research on the connection between hidden knowledge and physiological responses. Carl Jung's word association experiments in the early 1900s established the principle that emotionally significant stimuli produce measurable reaction time changes and physiological arousal — a foundational insight for all subsequent concealed information research. Harold Burtt, an early Ohio State researcher, contributed to understanding the relationship between deception and physiological responses through pioneering studies in the 1920s.
Joseph F. Kubis of Fordham University became an important figure in polygraph history when, in 1962, he became the first researcher to explore computer applications for polygraph chart analysis [25]Verified The Evolution of Lie Detection - The British Polygraph Society
Confirms Joseph F. Kubis of Fordham University was the first researcher to explore computer applications for polygraph chart analysis. His work laid the groundwork for the computerized scoring systems that would eventually transform polygraph practice worldwide. For more on the history of early polygraph formats, including the Relevant-Irrelevant Test, see our historical guide.
David Lykken and the Birth of the GKT
The CIT as a formal testing paradigm was introduced by David T. Lykken in his 1959 paper 'The GSR in the detection of guilt,' published in the Journal of Applied Psychology [3]Verified Memory detection with the Concealed Information Test: A meta analysis of skin conductance, respiration, heart rate, and P300 data
Confirms CIT effect sizes: d = 1.55 for SCR, d = 1.11 for RLL, d = 0.89 for HR, and d = 1.89 for P300. Lykken proposed the Guilty Knowledge Test as an alternative to the CQT, arguing that detecting concealed knowledge was a more scientifically tractable problem than detecting deception per se. His scoring method — assigning scores based on whether the critical item elicited the largest or second-largest response — remains foundational to CIT practice to this day.
Lykken's ideas found their most enthusiastic reception in Japan, where the information-detection framework resonated with both the scientific community and the legal culture. While the CQT continued to dominate American practice, Japanese researchers built upon Lykken's foundation to create the world's most extensive real-world CIT program. This divergence between American and Japanese approaches has shaped the field of psychophysiological detection for over six decades.
International Influence and Future Directions
Japan's Global Impact on CIT Research
Japan's field application of the CIT has had a profound impact on international research. The field data generated by approximately 5,000 annual examinations provides a level of ecological validity that laboratory studies alone cannot achieve. Researchers worldwide — including Ben-Shakhar in Israel, Meijer in the Netherlands, Gamer and Verschuere in Europe — have drawn on Japanese field experience to validate and extend CIT methodology.
In Germany, researchers studying the CIT as a potential forensic tool in European legal systems have been actively working to bring the CIT into broader use, though the complex history of polygraph use in Germany has created unique challenges. In the Netherlands, where the CIT attracted interest from both researchers and policymakers, the field data from Japan provided essential benchmarks for evaluating CIT performance under realistic conditions.
The contribution of international researchers like Don Grubin, who brought post-conviction sex offender testing to the UK, demonstrates how polygraph practices from one country can influence policy in another. Japan's CIT model offers a particularly compelling template for countries seeking a more scientifically grounded approach to polygraph testing.
Future Frontiers: P300, Reaction Time, and Beyond
NRIPS researchers are actively exploring how to enhance CIT accuracy through new physiological measures. The 2014 meta-analysis demonstrated that P300 event-related brain potentials achieved the largest mean effect size (d = 1.89) among all CIT measures [3]Verified Memory detection with the Concealed Information Test: A meta analysis of skin conductance, respiration, heart rate, and P300 data
Confirms CIT effect sizes: d = 1.55 for SCR, d = 1.11 for RLL, d = 0.89 for HR, and d = 1.89 for P300, suggesting significant potential for brain-based detection methods. Osugi's ongoing P300-CIT research explores how emotional arousal at memory encoding affects brain-based concealed information detection [23]Verified Akemi Osugi - Investigative Psychology Lab
Confirms Osugi was a CIT polygraph examiner for over ten years with Japanese police, now associate professor at Fukuyama University.
Recent studies on reaction time-based CIT have demonstrated strong capacity to diagnose recognition of concealed information, offering a potentially more accessible alternative to traditional autonomic measures. Research on facial information measures — including eye movement, pupil size, blinks, and facial skin temperature — is also showing promise as new CIT channels. Some of these facial measures can already be recorded using current polygraph devices in Japan [20]Verified The Current and Future Status of the Concealed Information Test for Field Use
Describes current CIT field practice in Japan, statistical discrimination methods, and future research directions including EEG and P300.
The integration of advanced technology with Japan's proven CIT methodology points toward an exciting future. Technologies like functional neuroimaging and thermal imaging are being evaluated alongside traditional polygraph approaches [26]Verified Beyond the Polygraph: Deception Detection and the Autonomic Nervous System
Review of deception detection methods beyond traditional polygraph, including fMRI, EEG, thermal imaging, and cognitive-based approaches. Japan's NRIPS, with its unique combination of scientific rigor and field experience, is positioned to lead the next generation of concealed information detection.
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Frequently Asked Questions
What is the Concealed Information Test (CIT)?
The CIT is a psychophysiological testing method that detects whether an examinee has knowledge of specific details of a crime. Unlike the Comparison Question Test (CQT), which attempts to detect deception, the CIT detects crime-relevant memory by presenting multiple-choice items and measuring which one triggers an involuntary recognition response. It was first introduced by David Lykken in 1959 as the Guilty Knowledge Test (GKT).
Why does Japan exclusively use the CIT instead of the CQT?
Japan adopted the CIT because it was more compatible with the country's legal culture and emphasis on scientific validity. The CIT's non-accusatory format fit naturally within Japan's cooperative criminal justice system. Additionally, Japanese legal standards demanded a polygraph method with a testable theoretical foundation. The centralized National Police Agency structure enabled uniform implementation once the CIT was adopted.
How accurate is the CIT in Japan's field application?
Japanese field data from more than 5,000 annual examinations shows an accuracy rate of approximately 90% for detecting deception. Meta-analyses of CIT research demonstrate mean correct detection rates of 78–86% for guilty subjects and 94–99% for innocent subjects, with an impressively low false positive rate averaging just 4.1%.
Who are the key researchers behind Japan's CIT standardization?
The primary current NRIPS researchers driving CIT standardization are Izumi Matsuda, Tokihiro Ogawa, and Michiko Tsuneoka. Former NRIPS polygraph examiner Akemi Osugi, now an associate professor at Fukuyama University, has also been instrumental in documenting and sharing Japan's CIT practices with the international community through publications and conferences.
Are CIT polygraph results admissible in Japanese courts?
Yes. Japan's Supreme Court accepted polygraph CIT results as admissible evidence in 1968. However, the results are rarely treated as primary evidence — only a few of the approximately 5,000 annual cases are discussed in court proceedings each year. The probative value of CIT results is considered relatively high when the test is properly administered.
How do Japanese polygraph examiners become certified?
All Japanese CIT examiners must complete a 3-month intensive training course at the Training Center of Forensic Science, affiliated with NRIPS. Trainees are selected from university graduates majoring in psychology or related technical fields. They learn psychophysiology, statistics, CIT principles, question construction, and physiological measurement and analysis techniques.
How does the CIT work in practice during a criminal investigation?
A consenting examinee is first interviewed to determine what they already admit knowing about the crime. The examiner then attaches sensors measuring skin conductance, heart rate, respiration, and pulse wave. Multiple-choice questions are presented about crime details, each with one relevant item among five or more plausible alternatives. Each item is presented three to five times in varying order. Differential physiological responses to the relevant item indicate recognition of concealed crime knowledge.
What physiological measures does the Japanese CIT system record?
Japanese CIT examiners typically record electrocardiography (ECG), respiratory movement, skin conductance, and pulse wave. Since 2005, Japan has used a portable digital polygraph system, and the latest version is capable of recording more than 20 channels of various physiological indices, including blood pressure, peripheral skin blood flow, and normalized pulse volume.
Sources & References
Confirms Japan is the only country using CIT exclusively, describes the field CIT process, proposes statistical scoring methods, and reports 4.1% false positive rate
Confirms Japanese law enforcement uses only the CIT for memory detection in real-life criminal investigations and the CQT is not used
Confirms CIT effect sizes: d = 1.55 for SCR, d = 1.11 for RLL, d = 0.89 for HR, and d = 1.89 for P300
Confirms NRIPS organizational structure with Fourth Department of Forensic Science responsible for polygraph examination
Confirms NRIPS polygraph research focus, portable digital polygraph system with 20+ channels, and cardiovascular response research
Provides definitive description of how CIT is practiced daily in Japanese criminal investigations with approximately 5,000 annual examinations and ~100 examiners
Confirms Keeler model 302 was introduced to Japan in 1953, YKK and TKK polygraphs developed in 1955, and examiner training at NRIPS since 1953
Confirms more than 5,000 polygraph examinations per year in Japan with approximately 90% accuracy rate
Confirms Supreme Court admitted polygraph results as evidence in 1968, describes CIT field procedures, and details searching CIT methodology
Confirms Iacono and Lykken survey results: 77% SPR and 72% APA Division 1 support for CIT, vs. 36% and 30% for CQT
The National Academy of Sciences comprehensive review of polygraph research including CIT and CQT methodologies
Confirms CIT training procedures at NRIPS, 3-month training course requirements, and describes CIT field practice in Japan
Confirms development of Japan's portable digital polygraph system in 2005
Confirms Matsuda's latent class discrimination method and within-individual CIT classification innovations
Developed and validated OSS and ESS computerized scoring methods, replacing subjective hand-scoring
OSS-3 demonstrated balanced sensitivity/specificity and outperformed 10 human scorers
International validation achieved mean accuracy of 90.1% demonstrating ESS validity across cultures
Formalized the Utah-CQT numerical scoring system achieving highest rates of criterion accuracy and inter-rater reliability
Confirms detection rates of 78-86% for guilty and 94-99% for innocent subjects, overall effect size of 1.55, and optimal conditions effect size of 3.12
Describes current CIT field practice in Japan, statistical discrimination methods, and future research directions including EEG and P300
Reports CIT sensitivity of 83% and specificity of 91% in mock-theft experiment
Confirms Michiko Tsuneoka's affiliation with NRIPS Fourth Department as senior researcher working on concealed information test
Confirms Osugi was a CIT polygraph examiner for over ten years with Japanese police, now associate professor at Fukuyama University
Confirms Osugi's 2025 presentation on Japanese CIT at International Polygraph Conference in Hungary and P300-CIT research
Confirms Joseph F. Kubis of Fordham University was the first researcher to explore computer applications for polygraph chart analysis
Review of deception detection methods beyond traditional polygraph, including fMRI, EEG, thermal imaging, and cognitive-based approaches
Confirms NRIPS is located in Kashiwa, Chiba Prefecture, Japan, and is an attached organization of the National Police Agency
Confirms Ben-Shakhar and Elaad meta-analysis findings: overall effect size of 1.55 for SCR across 80 studies, 77% SPR support for CIT
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