A polygraph, commonly known as a lie detector, measures a person's physiological responses like breathing, pulse, blood pressure, and perspiration when answering questions. It was developed in the early 20th century and works by detecting changes in the autonomic nervous system which controls involuntary body functions. However, polygraph results are not completely reliable and accuracy depends on the quality of the test being administered. Error rates have been estimated to be as high as 40% depending on the study. Some individuals may be wrongly identified as lying or certain trained persons can pass the test despite being deceptive.
The polygraph test is used to test the truthfulness of a subject and gives its results on the basis of several physiological indices when the subject is asked a series of questions. The reports of this test can be used as a corroborative evidence in courts.
a machine designed to detect and record changes in physiological characteristics, such as a person's pulse and breathing rates, used especially as a lie detector.
The polygraph test is used to test the truthfulness of a subject and gives its results on the basis of several physiological indices when the subject is asked a series of questions. The reports of this test can be used as a corroborative evidence in courts.
a machine designed to detect and record changes in physiological characteristics, such as a person's pulse and breathing rates, used especially as a lie detector.
This presentation is regarding the technology involved in the polygraph machine. It describes the procedures involved in carrying out the so called 'Lie detector ' test for criminal investigation and other purposes.
Easily share what happened during the past month with a beautiful presentation from Venngage. Bring attention to your accomplishments with graphs, charts, and engaging icons. With a presentation from Venngage your audience will be on the edge of their seats.
Easily share what happened during the past year with a beautiful presentation from Venngage. Bring attention to your accomplishments with graphs, charts, and engaging icons. With a presentation from Venngage your audience will be on the edge of their seats.
This presentation is regarding the technology involved in the polygraph machine. It describes the procedures involved in carrying out the so called 'Lie detector ' test for criminal investigation and other purposes.
Easily share what happened during the past month with a beautiful presentation from Venngage. Bring attention to your accomplishments with graphs, charts, and engaging icons. With a presentation from Venngage your audience will be on the edge of their seats.
Easily share what happened during the past year with a beautiful presentation from Venngage. Bring attention to your accomplishments with graphs, charts, and engaging icons. With a presentation from Venngage your audience will be on the edge of their seats.
Easily share your biggest accomplishments with your audience using graphs, charts, and engaging icons. With a presentation from Venngage your audience will be on the edge of their seats.
The name of Athens, connected to the name of its patron goddess Athena, originates from an earlier Pre-
Greek language.
The etiological myth explaining how Athens acquired this name through the legendary contest between Poseidon and Athena was described by Herodotus, Apollodorus, Ovid, Plutarch, Pausanias and others.
Plato, in his dialogue Cratylus, offers his own etymology of Athena's name connecting it to the phrase ἁ θεονόα or hē theoû nóēsis (ἡ θεοῦ νόησις, 'the mind of god')
http://inarocket.com
Learn BEM fundamentals as fast as possible. What is BEM (Block, element, modifier), BEM syntax, how it works with a real example, etc.
How NOT to Run Your Company – Lessons LearnedWeekdone.com
The Internet is full of articles on „How to succeed“ and „How to build a great company“ But while following those guidelines we often forget that there's a lot you just can't do.
Learning from your own mistakes is good, but it's even better when you can learn from the mistakes of others.
Everyone's favorite billionaire and Republican presidential hopeful Donald Trump has said “Watch, listen, and learn. You can’t know it all yourself. Anyone who thinks they do is destined for mediocrity.”
Enjoy the slides and a sense of humor is advised.
Tips from Calvin and Hobbes on how to be a good customerFreshdesk Inc.
What could a careless, mischievous six year old possibly teach you about being a good customer? Well, not much really, but he can surely tell you a lot about what you should NOT do.
Here are a few things you can learn from Calvin about being a good customer.
For more tips on customer support, head over to the Freshdesk blog - http://blog.freshdesk.com/
The colours that dresses your brand are playing an important role in how they support this personality that you want to portray. Don’t panic when a colour speaks one thing, but in the relation to the brand it delivers a slightly different response.
Check out these examples of how brands used in conveying their message through branding and banner advertisement.
Read more http://www.bannersnack.com/blog/color-banner-design-inspiration/
Lightning Talk #9: How UX and Data Storytelling Can Shape Policy by Mika Aldabaux singapore
How can we take UX and Data Storytelling out of the tech context and use them to change the way government behaves?
Showcasing the truth is the highest goal of data storytelling. Because the design of a chart can affect the interpretation of data in a major way, one must wield visual tools with care and deliberation. Using quantitative facts to evoke an emotional response is best achieved with the combination of UX and data storytelling.
Clickbait: A Guide To Writing Un-Ignorable HeadlinesVenngage
We looked at some of the top performing content on social media, from some of the top publications on the web. From this, we were able to figure out the recipe for crafting a click-worthy title. Here is what we learned...
Visit us at gykantler.com for more information.
The concept of a “brand” is no longer taboo at B2B companies. In fact, strong B2B brands outperform weaker ones by as much as 20%, according to recent research by McKinsey. Yet it’s not easy for ROI-obsessed marketers to justify spending money on their brand, which can be difficult to track. As a result, your brand is too often left either underfunded or on the back-burner altogether.
We’re going to help you solve this. In this presentation you’ll learn:
- How your brand can boost demand generation and other key performance indicators
- The elements of a B2B brand and how those are different from traditional consumer branding
- How to elevate your brand through B2B marketing channels and brand advocates
- Metrics to track the impact of your brand
Dispatches From The New Economy: The Five Faces Of The On-Demand EconomyIntuit Inc.
From people determined to be their own boss, to those embracing the flexibility to do something they love, to workers finding a replacement for a traditional job – people working in the on-demand economy are just about as diverse as the labor market itself. A new report from Intuit Inc. and Emergent Research shows that there are a broad range of motivations – and differing levels of satisfaction – among five distinct groups of on-demand workers:
The Business Builders – primarily driven by the desire to be their own boss. They represent 22 percent of on-demand workers.
The Career Freelancers – happily building a career through independent work. They represent 20 percent of on-demand workers.
The Side Giggers – looking to find financial stability by supplementing existing income. They represent 26 percent of on-demand workers.
The Passionistas – looking for the flexibility to do something they love. They represent 18 percent of on-demand workers.
The Substituters – replacing a traditional job that is no longer available. They represent 14 percent of on-demand workers.
Methodology
A total of 4,622 workers who find work opportunities via the platforms provided by the participating partner companies completed an online survey between September 11 and October 1, 2015. The results were weighted to reflect the proportion of workers in each of the following segments: Drivers/Delivery, Online Talent Marketplaces and Field Service/Onsite Talent. The weights were developed using earlier survey work that sized the on-demand economy. The largest weighted share of on-demand worker respondents from any single company is 16%, with most partner companies providing less than 10% of the respondents.
10 Engagement Lessons Learned From 1 Million Survey AnswersD B
Officevibe released a research report called The State of Employee Engagement based on 1,200,000 survey answers from employees in 157 countries. After analyzing the data, we discovered some truly shocking statistics about the state of engagement across the world.
This actionable webinar will show you how you can keep your employees happy and productive.
See the recording of the webinar:
http://bit.ly/2gjJg3o
Get all the free bonuses and extra tips:
http://bit.ly/2g7Q3xM
Content by Officevibe, the simplest tool for a greater workplace.
What happens when the digital tools and platforms we make and use for communication and entertainment are hijacked for terrorism, violence against the vulnerable and nefarious transactions? What role do designers and developers play? Are we complicit as creators of these technologies and products? Should we police them or fight back? As Portfolio Lead for Northern Lab, Northern Trust's internal innovation startup focused on client and partner experience, Antonio will share a mix of provocative scenarios torn from today's headlines and compelling stories where activism and technology facilitated peace—and war.
As a call-to-action for designers and developers to engage in projects capable of transformational change, he'll explore the question: How might technology foster new experiences to better accelerate social activism and make the world a smarter, safer place?
Get Featured: So You Want to be on the Front Page of SlideShare?Venngage
After trying to figure out whether or not there is a secret formula for getting featured on the SlideShare homepage, we decided to ask 13 pros who have been featured on multiple occasions. We created this deck to share their insights with you!
Featuring tips from:
Robert Katai
Julius Solaris
Jen Jones
Sandra Jovanovic
Ross Simmonds
Michael Brenner
Joe Gelman
Steve Williamson
Stephen Jeske
Ayesha Ambreen
Josh Steimle
Eugene Cheng
Pamela Pavliscak
Read their full and in depth tips here: https://venngage.com/blog/get-featured-slideshare/
Nobody can discover the world for somebody else. Only when we discover it for ourselves does it become common ground and a common bond and we cease to be alone.”
The technologies and people we are designing experiences for are constantly changing, in most cases they are changing at a rate that is difficult keep up with. When we think about how our teams are structured and the design processes we use in light of this challenge, a new design problem (or problem space) emerges, one that requires us to focus inward. How do we structure our teams and processes to be resilient? What would happen if we looked at our teams and design process as IA’s, Designers, Researchers? What strategies would we put in place to help them be successful? This talk will look at challenges we face leading, supporting, or simply being a part of design teams creating experiences for user groups with changing technological needs.
38 Employee Engagement Ideas Your Team Will LoveElodie A.
Team building is an important part of making employees happy. Here are 38 employee engagement ideas you can use right away with your team.
Read more on Officevibe blog:
https://www.officevibe.com/blog/employee-engagement-ideas-team-will-love
Learn more about Officevibe, the simplest tool for a greater workplace:
https://www.officevibe.com/
Download the FREE guide about the 10 pillars of employee engagement:
http://hs.officevibe.com/complete-guide-employee-engagement?utm_source=slideshare&utm_medium=social&utm_campaign=38-engagement-ideas-your-team-will-love&utm_content=employee-engagement-ebook
Forensic and criminal psychology is the field that applies psychological principles and techniques to understand criminal behavior, investigate crimes, and provide expert testimony in legal settings. It involves studying the motives, personality traits, and cognitive processes of offenders, as well as conducting evaluations and interventions to aid in the criminal justice system. Various instruments are used for such analysis like- Brain-mapping, Narco-analysis, Polygraph etc.
A polygraph, commonly known as a lie detector, is a device used to measure physiological responses in an individual during questioning. It records changes in heart rate, blood pressure, and other indicators to determine if someone is being deceptive.
Polygraph Testing Management Plan through Psychotherapy CBT, Behavior Therapy...research gate
Polygraph Testing Management Plan through Psychotherapy CBT, Behavior Therapy, REBT
Polygraph testing involves the use of an instrument which detects and measures some of the physiological changes that take place in the human body when a person lies. These tests are particularly prevalent in the retail industry.Polygraph tests are used frequently in many fields, such as law enforcement, national security, and private investigations. The exam is typically broken down into four phases: the initial interrogation and pre-test phase, the in-test (polygraph exam), and the post-test phase.The primary purpose of the polygraph test in security screening is to identify individuals who present serious threats to national security. To put this in the language of diagnostic testing, the goal is to reduce to a minimum the number of false negative cases (serious security risks who pass the diagnostic screen).
I am Clinical psychologist & I have great experience in this feild.I having many other skills .As a writer, I would consider myself to be a very strong writer. When it comes to writing or having different writing assignments, I have to write everything down on a piece of paper to get my thoughts out and just let my pen flow. I tend to write essays only when I am assigned, but for the most part, I write everyday. I personally like to write about me in particular but mainly I enjoy writing about overcoming different obstacles people face in life .
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The PowerPoint presentation seamlessly guides through the scientific lie detector, flowing from its overview and historical roots to discussions on validity, reliability, purpose of use, target users, procedural steps, necessary setup, limitations, and adherence to regulations.
What are the different types of sleep apnea tests.pptxleelindesy
Among the several sleep problems that affect people, sleep apnea is a prevalent one. In this condition, patients fail to rest well at night because of obstruction in the airway. As a result, they always feel exhausted and tired.
Prof. Todor (Ted) A. Popov - 6th Clinical Research ConferenceStarttech Ventures
Ομιλία - Παρουσίαση: Prof. Todor (Ted) A. Popov, Professor of Medicine, Medical University in Sofia, Chairman of the Bulgarian Ethics Committee for Multicenter Studies
Τίτλος Παρουσίασης: «Do databases around the world speak the same language?»
This documentation details the design of a Distributed Web content caching system in a LAN, using the SDN OpenFlow model. This system was successfully implemented on GENI (Global Environment for Network Innovations) to test the performance improvements.
This distributed web-caching helps reduce access delays of frequently requested web content (web pages, files - pdfs, images,etc.) within the LAN by more than 50% compared to a LAN without this caching system. Further, this model helps in reducing load on the access links as every repeated request need not be fetched from the main server located in some other geographical area.
The distribution of caching servers in the LAN aim at load balancing the requests and also tackle the issue of single point of failure as in a centralized caching system.
Tactile sensing techniques and comparative analysis of commercialAasheesh Tandon
This deals with briefly listing different methods of achieving tactile (touch) sensing, and then some commercial tactile sensors available in the industry. Finally, a comparison has been made among them.
A STUDY OF INFRA-RED IMAGING SENSORS AND INSTRUMENTS ON GEO-STATIONARY SATELL...Aasheesh Tandon
This deals with the different types of imaging sensors, its constituents, thermal control systems, satellite communication, sensor detector assemblies, sensor design.
This presentation explains what is a survey/review paper.
Moreover it deals with the aspects that have to be kept in mind while writing a review paper.
Tactile sensors and their robotic applicationsAasheesh Tandon
This presentation discusses about artificial tactile sensors, it's comparison with human tactile senses. Further different types of tactile sensors are enlisted ,with a few given in more detail.
Robotic applications are also discussed and then finally future developments in this area is mentioned.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
2. WHAT IS A POLYGRAPH?
• A polygraph, often called a “Lie Detector,” is a
machine that measures human responses to
questions, measuring a lot of physiological
symptoms of anxiety or emotion to estimate if
the subject is being truthful or not.
3. A BRIEF HISTORY
• William Moulton Marston : creator of the systolic
blood pressure test - one component of the modern
polygraph.
• John Augustus Larson : first American police officer
to use polygraph in criminal investigations.
• Leonarde Keeler : was the co-inventor of the
polygraph.
John Augustus LarsonWilliam Moulton Leonarde Keeler
4. HOW DOES IT WORK ?
• Polygraph machine records multiple signals
using 4 to 6 sensors attached to the patient’s
body. The sensors usually record:
• The person's breathing rate
• The person's pulse
• The person's blood pressure
• The person's perspiration
5.
6. HOW DOES IT WORK ?
The Nervous System reacts to different situations
differently.
For this, it uses different parts of it, namely :
I. Somatic Nervous System
II. Autonomic Nervous System
a) Sympathetic Nervous System
b) Parasympathetic Nervous System
Arousal Increased ANS activity Lie
7. THE INSTRUMENTATION
• Cardio – Sphygmograph : collects blood pressure and
heart rate data
• Pneumograph : measures respiratory patterns
• Galvanograph : measures electro-dermal activity or sweat
8. ADMINISTRATION OF THE TEST
• Familiarizing the subject with the test
• Pre-test Interview
• Formulating Questions
• Analysis of the result
9. TYPICAL QUESTIONNAIRE
The Relevant – Irrelevant Test
Comparison Question (Control Question) Test
Reid Comparison Question Test
Zone Comparison Test
Concealed Information Test
Peak-of-tension Test
10.
11. ACCURACY
• U.S. Attorney General John Ashcroft concedes that
polygraphs used in federal agencies have an error rate
of about 15% . Some critics even assert that credible
scientific research has found that commonly used
polygraphs have error rates of 40% or more, only
slightly better than flipping a coin to decide if a subject
is lying .
• A truth-teller might recognize that a question has
significance in the investigation and exhibit the same
increased cardiovascular and sweat activity as a liar.
This innocent subject may be wrongly accused of lying,
with very serious and unjust consequences.
• Some people, such as spies, are trained to disguise
their feelings, can lie very naturally, and can easily pass
polygraph tests.
Editor's Notes
A student in experimental psychology at Harvard University, William M. Marston invented the modern polygraph prior to 1921. His treatise The Lie Detector Test on understanding physiological responses related to deception was published in 1938. John A. Larson, a police officer in Berkeley, California, modified Marston's polygraph, developing a technique for continuous recording of physiological responses. One of Larson's colleagues, Leonarde Keeler, added the gavanograph component to the polygraph. He joined the faculty of Northwestern University School of Law in Chicago in 1930 and established the Keeler Polygraph Institute of Chicago.
Lawyer, John E. Reid played an important role in the development of questioning techniques used during a polygraph test. In a 1947 paper, he described the use of control questions to evoke emotional responses. In collaboration with Cleve Backster's work, this idea eventually became the Control Question Test (CQT), which is used by the majority of forensic psychophysiologists today.
During the 1960s and 1970s, the polygraph business grew rapidly.
During the late 1970s and early 1980s, the use of the polygraph by the military and security agencies expanded drastically.
In the 1980s the scientific validity of polygraphs was brought into question by psychologists. In 1988, the federal Polygraph Protection Act was passed, prohibiting employers from using polygraphs for employment screening.
The Nervous System reacts to different situations differently. For this, it uses different parts of it. Namely, somatic And autonomic nervous system.
Somatic nervous system controls organs under voluntary control (mainly muscles) and the autonomic nervous system regulates individual organ function and homeostasis, and for the most part is not subject to voluntary control.
Lying involves the Autonomic Nervous system. It's commonly believed that when someone lies, changes occur such as increased heart rate. It’s neater, for the physiological systems of the body, to tell the truth instead of lying. Lying, in normal and mentally healthy beings (not sociopathic), causes the body to develop “mental stress”.
The Autonomic Nervous System is most important in two situations, those emergency situations that cause stress and require us to "fight" or take "flight" (run away) and those non-emergency situations that allow us to "rest" and "digest".
The autonomic nervous system is responsible for monitoring conditions in the internal environment and bringing about appropriate changes in them. There are two major components of the autonomic nervous system, the sympathetic and the parasympathetic systems.
When the subject has an emotional response associated with the telling of a falsehood, the sympathetic NS tends to fire off all at once (flight or fight response) in such situations and all sorts of physiological functions are altered. For example, heart rate goes up, pattern of respiration changes, blood pressure goes up, and production of sweat by glands in the skin of the hand goes up. Thus Arousal Increased ANS activity.
Specific patterns of arousal during questioning could indicate guilt or lying.
Using the polygraph instrument, physiological data is collected from three major systems, including (a) the cardiovascular system – heart rate, blood pressure, and blood volume; (b) the respiratory system – movement of the chest cavity; and (c) the endocrine system – sweat gland activity. The polygraph instrument may also detect other responses like arm and leg movement
Respiratory patterns are measured by pneumographs, which are devices that record thoracic movements or volume change during respiration. One of the pneumograph tubes is strapped around the chest of the examinee and the other is placed around his or her abdomen. Each pneumograph is connected to the polygraph machine by an air-filled rubber tube. When the examinee breathes in and out, the air pressure in the tubing changes to reflect his or her breathing rate and frequency. The polygraph instrument records these responses. Respiratory responses that may point toward deception include shortness of breath and laboured breathing.
Cardio-sphygmograph component of the polygraph. An arm-encircling cuff that is placed around the upper arm collects blood pressure and heart rate data. The cuff is filled with air and connected to the polygraph machine by air-filled tubes. As blood pumps through the examinee’s arm, changes in blood pressure will alter the amount of air pressure in the cuff; these changes are recorded by the machine. Physiological responses such as a faster heart rate and an increase in blood pressure may suggest deception
Galvanograph. The measurement of electro-dermal activity – or sweat – is conducted by fingerplates that are attached to two of the examinee’s fingers. These plates measure the skin’s ability to conduct electricity. Dry skin is a poor conductor of electricity. If the examinee perspires, however, then the water and salt from the sweat will reduce resistance and allow a larger amount of electric current to travel along the surface of the skin. This increase in current reflects the amount of sweat produced in the examinee’s fingertips. Polygraph practitioners believe that an individual sweats more when placed under stress, and so sweaty fingertips may point toward deception
Familiarizing the subject with the test
This includes familiarizing the subject with the examination room, polygraph instrument & attachments, giving instructions about the manner in which he has to sit through for examination, attaching the accessories, recording of normal physiological responses and instructing the examinee regarding the administration of the questionnaire.
Pre-test Interview
During the polygraph test, the examiner and the subject are alone in the questioning room. Before the test begins, the examiner spends about an hour talking with the subject. Most forensic psychophisiologists consider this pretest phase an extremely important part of the polygraph. The examiner obtains a baseline read on his or her emotional state and develops the questions that are asked during the actual test. Before the test begins, the examiner goes over each question with the subject so that he or she knows exactly what to expect. When they are ready start, the person administering the polygraph attaches the various components of the polygraph instrument to the examinee.
Formulating Questions
Different perspectives are employed using different sets of questions.
Analysis of the result
Employing the above mentioned knowledge, the results obtained from the polygraph are compared to a global scale. As a general rule, the frequency of the patterns obtained increases during ANS Shooting of the impulses, which might indicate a falsehood, on the part of the subject.
Relevant – Irrelevant test : the relevant-irrelevant test format compares examinee responses to relevant and irrelevant questions. A relevant question is one that deals with the real issue of concern to the investigation. These questions include asking whether the examinee perpetrated the target act or knows who did it and perhaps questions about particular pieces of evidence that would incriminate the guilty person. An irrelevant question is one designed to provoke no emotion (e.g., “Is today Friday?). Irrelevant questions are typically placed in the first position of a question list because the physiological responses that follow the presentation of the first question are presumed to have no diagnostic value; they are also placed at other points in the question sequence. Guilty examinees are expected to show stronger reactions to relevant than to irrelevant questions; innocent examinees are expected to react similarly to both question types.
Comparison question tests (also called control question tests) compare examinees’ responses to relevant questions to their responses to other questions that are believed to elicit physiological reactions from innocent examinees. Relevant questions are defined as in the relevant-irrelevant test. Comparison questions ask about general undesirable acts, sometimes of the type of an event under investigation. For example, in a burglary investigation, one comparison question might be “Have you ever stolen anything?” In probable-lie comparison question tests, the instructions are designed to induce innocent people to answer in the negative, even though most are lying. Innocent examinees are expected to experience concern about these answers that shows in their physiological responses. In directed-lie tests, examinees are instructed to respond negatively and untruthfully to comparison questions (e.g., “During the first 20 years of your life, did you ever tell even one lie?”). In both forms of test, the expectation is that innocent examinees will react more strongly to the comparison questions, and guilty examinees will react more strongly to relevant questions.
The Reid comparison question test, also known as the modified general question test, was the earliest form of comparison question test. It includes probable-lie comparison questions and is interpreted by the examiner’s global evaluation of the charts, combined with other observations made during the examination. Other characteristics of the test include a discussion of the examinee’s moral values during the test procedure and the use of a “stimulation” test between the first and second presentations of the questions.
The zone comparison test is named for the three “zones” or blocks of time during the test: the relevant questions (called the red zone), the probable-lie comparison questions (the green zone), and other questions (the black zone). Black zone questions are included to uncover examinee concerns about an issue outside of the scope of the red and green zones, such as involvement in another crime. Each zone is presumed to be threatening to someone; however, depending on the examinee’s mental set, it is anticipated that one particular zone is more threatening than are the other two.
Concealed information tests (more often called guilty knowledge or concealed knowledge tests) present examinees with sets of very similar items, much in the manner of stimulation tests, except that the similar items include one true and several (usually, four) false details of some aspect of an incident under investigation that has not been publicized, so that the true answer would be known only to the investigators and to those present at the incident. In a burglary, examinees might be asked about several possible points of entry into the house, one of which the burglar actually used. (For more detail about question construction and administration of concealed information tests, see Nakayama [2002].) When an examinee is asked whether he or she used each of these routes, the answer is expected to be negative regardless of the examinee’s innocence or guilt. Guilty examinees are expected to reveal their concealed knowledge by responding more strongly to the true item than to the others.
Concealed information tests are applicable only under restricted conditions: when there is a specific incident, activity, or thing that can be the subject of questioning and when there are several relevant details that are known only to investigators and those present at the incident. Thus, these tests are not applicable in typical screening situations in which the only possible relevant questions concern generic events, such as unspecified acts of espionage that may or may not have occurred.
The peak-of-tension test is similar in format to concealed information tests, but is distinct because questions are asked in an easily recognized order (e.g., “Was the amount of stolen money $1,000? $2,000? $3,000?” etc.). A guilty examinee is expected to show a pattern of responsiveness that increases as the correct alternative approaches in the question sequence and decreases when it has passed. Stimulation tests often have this format. In a known-solution peak-of-tension test, the examiner knows which alternative is the one truly connected to the incident and evaluates the examinee’s pattern of responses for evidence of involvement in the incident. It is also possible to use the peak-of-tension test in a searching mode when the examiner does not know which answer is connected to the event but wants to use the test for help in an investigation. It is assumed that the pattern of a guilty person’s autonomic responses will reveal the correct answer.
Despite the subjectivity and perhaps spurious assumptions associated with the polygraph, it is still widely used throughout the nation. The range of error in which the polygraph operates is at the root of the debate over whether polygraph tests should be administered at all. U.S. Attorney General John Ashcroft concedes that polygraphs used in federal agencies have an error rate of about 15% . Some critics even assert that credible scientific research has found that commonly used polygraphs have error rates of 40% or more, only slightly better than flipping a coin to decide if a subject is lying .
These errors are not usually in the physical measurements made by the machine, but rather are embedded in the assumption that physiological conditions can indicate the psychological state of lying. Critics question the theory by which the polygraph operates, rather than the quantitative measurements it provides. It may be generally true that when people lie, they exhibit certain physiological phenomena. However, there may be other reasons for an honest subject to demonstrate these same physiological signs. For example, a truth-teller might recognize that a question has significance in the investigation and exhibit the same increased cardiovascular and sweat activity as a liar. This innocent subject may be wrongly accused of lying, with very serious and unjust consequences.
Some people, such as spies, are trained to disguise their feelings, can lie very naturally, and can easily pass polygraph tests. Furthermore, since polygraphs rely heavily on interpretation by polygraph examiners, human error and bias can create inaccuracy in the results. Why, then, is the polygraph still used today? First, the willingness to undergo a polygraph test often provides proof that the subject has nothing to conceal. Second, the response to certain questions in the polygraph tests can sometimes lead investigators to new focuses . Finally, fear of the test can prompt the guilty to confess.