Polygraph Technique - Vocabulary Flashcards

Vocabulary flashcards covering key terms and definitions from the Polygraph Technique lecture notes.

Polygraph Examination

An investigative/technical aid used in investigations to obtain admissions or confessions; not a substitute for investigation and not a lie detector.

Admission

A statement of fact by the accused that does not necessarily acknowledge guilt in committing the offense.

Confession

A voluntary declaration acknowledging that the person committed or participated in the crime.

Mechanical Basic Premise

The polygraph machine can generate graphical records containing reliable information about physiological changes.

Physiological Basic Premise

Physiological changes occur after stimulation of specific nervous system components and can be reliably diagnosed.

Psychological Basic Premise

Stimulation of specific nervous system components can be detected by involuntary mental/emotional processes when a person tries to conceal deception.

Blood Pressure and Heartbeat Frequency

Increases in blood pressure and heart rate after relevant questions, with breathing suppression as a deception indicator.

Systolic

High arterial pressure during heart contraction (top number on a BP reading).

Diastolic

Low arterial pressure during heart relaxation (bottom number on a BP reading).

Ink Curve (Heartbeat Graph)

The polygraph’s moving graph showing beat frequency and systolic/diastolic pressures.

Heart Autonomy

The heart continues to beat automatically, even outside the body or with proper blood supply.

Sympathetic Set

The part of the autonomic system that accelerates the heartbeat.

Cranial Autonomic System

The part of the autonomic system that can retard the heartbeat.

Adrenaline

A hormone that increases heartbeat frequency.

Breathing (Inspiration and Expiration)

Two steps of breathing: inspiration (inhalation) and expiration (exhalation).

Electro-dermal Response

Skin resistance changes in response to external stimuli; categories include Normal and Abnormal.

Normal Response

A standard electro-dermal response not associated with deception.

Abnormal Response

Unusual electro-dermal responses that may indicate deception or disruption.

Machine Fright Response

Abnormal electro-dermal response appearing on initial questions or early in the test.

Physical Movement Response

Abnormal electro-dermal response due to muscular movement during the test.

Outside Interference Response

Abnormal response caused by unfamiliar external noises or events at the test location.

Mental Tie-up Response

Also called a guilt complex; a mental state contributing to deception indicators.

Deception Response

Abnormalities in responses that result from lying.

Single-issue Polygraph Exam

A polygraph exam focused on one issue; accuracy typically 95–98% when properly conducted by a qualified examiner.

Accuracy

The degree to which polygraph results correctly indicate truth or deception.

Factors Affecting Accuracy

Instrument quality, subject condition, room condition, and examiner qualifications.

Nervousness (truthful subjects)

Extreme emotional tension in truthful subjects can produce false indicators of deception.

Physiological Abnormalities

Physiological issues such as abnormal blood pressure or heart/respiratory diseases that affect results.

Mental Abnormalities

Mental conditions (e.g., feeblemindedness) that can affect polygraph interpretations.

Beat the Machine

Attempt to manipulate results through controlled breathing or muscular tensing.

Unobserved Muscular Pressure

Applying muscle pressure covertly, causing ambiguities in blood pressure readings.

Limitations of the Polygraph

An investigative aid, not a lie detector; results depend on examiner competence and proper procedures.

Consent to Test

The test will not be administered without the voluntary consent of the subject.

Guilt by Refusal

No inference of guilt is drawn if a subject refuses to take the test.

Accusations Explained

The test will not be conducted until the accusations have been explained to the subject.

Barriers to Polygraph Examination

Factors that make analysis impossible, including Pathological Liar and Mental Cases.

Pathological Liar

A person who lies habitually; a barrier to accurate polygraph interpretation.

Mental Cases

Individuals with mental conditions that can affect polygraph results.