Chapter 2: Deception Detection Flashcards
What are the methods of deception which are currently being used or applied by law enforcement agencies?
- Use of a polygraph or a lie detector machine or Autonomic Indicators
- Use of the word association test
- Use of the psychological stress evaluator
- Measurement of Brain Function
- By observation / Demeanor or Behaviours
- Direct Investigation
- Administration of “truth serum’’
- Narcoanalysis or narcosynthesis
- Intoxication
- Hypnotism
- Scientific interrogation
- Confession
What is a lie detector?
A lie detector records physiological changss that occur in association with lying in a polygraph
The instrument (lie detector) is like an electrocardiogram (ECG) or electroencephalogram (EEG) with recording stylets making tracings on moving paper at the rate of 6 inches per minute.
What are the requisites in conducting a lie detector test?
- The test must be made in a room especially built for the purpose. It must be quiet, private, sound-proof and free from any disturbances and distractions. Extrenuous noises, like blowing of horns, ringing of bells or telephone and loud conversations of persons must be avoided.
- The subject is seated on a chair beside a table where the instrument is located. The pneumograph tubes are placed around the chest and abdomen, the blood pressure cuff around the upper right arm, and the electrodes are attached to the two fingers of the other hand. All the gadgets attached are connected to the recording instrument.
- The subject must be placed in a position so that he looks straight ahead; instructed to remain as quiet as possible; to answer all questions by “yes” or “no”; to refrain from other verbal responses during the test.
What are the phases of the examination in a lie detector test?
(P-A-P)
- Pre-test interview
- Actual interrogation and recording through the instrument
- Post-test interrogation
What is the purpose of a pre-test interview in a lie detector test?
- To determine whether the subject has any medical or psychiatric condition or has used drugs that will prevent the testing;
- To explain to the subject the purpose of the examination
- To develop the test questions, particularly those of the of the technique
- To relieve the truthful subject of any apprehension as well as to satisfy the deceptive subject as to the efficiency of the technique
- To know any anti-social activity or criminal record of the subject.
What are the standard set of questions asked in a lie detector test?
Irrelevant questions — These are questions which have no bearing to the case under investigation. The question may refer to the subject’s age, educational attainment, marital status, citizenship, occupation, etc. The examiner asks these types of questions to ascertain the subject’s normal pattern of response by eliminating the feeling of apprehension.
**Relevant questions **— These are questions pertaining to the issue under investigation. They must be unambiguous, unequivocal and understandable to the subject. They must all be related to one issue or one criminal act. It is equally important to limit the number of relevant questions to avoid discomfort to the subject. Relevant questions must be very specific to obtain an accurate result.
Control questions — These are questions which are unrelated to the matter under investigation but are of similar nature although less serious as compared to those relevant questions under investigation.
When is a person considered as telling the truth in a lie detector test?
In practice, the relevant — irrelevant question technique is used. The responses to the two types of questions are com- pared, if there is no significant difference between the relevant and irrelevant questions, the subject is reported to be truthful.
However, if the subject responds more to the relevant questions, he is considered as not telling the truth.**
What is the role of the control questions in a lie detector test?
The use of control questions is considered by many poly- graphists to be the most reliable and effective questioning technique.
These are usually asked if there is doubt in the interpretation of the subject’s response to relevant and irrelevant questions.
Are the results taken from lie detector tests admissible in court?
Not admissible
What are the reasons why the result of a lie detector or polygraph test is inadmissible?
- The polygraph techniques are still in the experimental stage and have not received the degree of standardization of acceptance among scientists.
- The trier of fact is apt to give almost conclusive weight to the polygraph expert’s opinion.
- There is no way to assure that a qualified examiner administered the test.
- Since the polygraph involves a certain unconscious quality of the examinee, he may unwittingly waive his or her right against self-incrimination.
- The test itself cannot be relied upon because it has many errors.
What are the factors that are responsible for the 25% errors of the lie detector tests?
- Nervousness or extreme emotional tension
- Physiological abnormalities
- Mental abnormalities
- Unresponsiveness in a living or guilty subject
- Attempt to “beat the machine” by controlled breathing or by muscular flexing.
- Unobserved application of muscular pressure which produces ambiguities and misleading indications in the blood pressure tracing
Can a person be compelled to be subjected to a lie detector test?
No, a person cannot be compelled to be subjected to the test since it infers the use of intelligence and attention or other mental faculties which is self-incriminatory.
What is phrenology?
Phrenology is the study of the conformation of the skull as indicative of mental faculties and traits of character.
What is a polygraph?
A polygraph, often incorrectly referred to as a lie detector test, is a device or procedure that measures and records several physiological indicators such as blood pressure, pulse, respiration, and skin conductivity while a person is asked and answers a series of questions.
What is cardiosphygmograph?
The Cardiosphygmograph measures the subject’s blood pressure and heart rate.
It consists of a blood pressure cuff, a rubber pump, and a sphygmomanometer. When the blood pressure cuff is wrapped around the subject’s right arm, its rubber portion is placed over the brachial artery, ensuring a more accurate reading.
What is a pneumograph?
A pneumograph, also known as a pneumatograph or spirograph, is a device for recording velocity and force of chest movements during respiration.
What is the use of a galvanograph?
The Galvanograph measures a person’s perspiration. It comprises electrical sensors known as galvanometers, which are attached to the person’s fingertips. Fingertips are a good location for measuring perspiration since they contain many sweat glands.
What is a polygraphist?
A person skilled in the operation of a polygraph (lie detector)
What are the purposes of a polygraph?
- Pre-employment in law enforcement or pre-clearance screening in agencies involved in national security
- Screening of current employees, especially in security-sensitive occupations
- Specifice incident investigations (e.g., criminal cases)
What consists of the nervous system?
The nervous system consists of:
1. The Central Nervous System (CNS) which includes the brain and the spinal cord;
2. The Peripheral Nervous System (PNS) which consists of the nerves that branch out from the brain and spinal cord. The peripheral nervous system is further subdivided into the somatic nervous system and the autonomic nervous system.
