CPE CPE Instrument Technology 2 — Questions and Answers
Question 1: What is the recommended cuff inflation pressure range for the cardio component during a polygraph examination?
- 20–40 mmHg
- 40–60 mmHg
- 60–90 mmHg (Correct answer)
- 100–120 mmHg
Correct answer: 60–90 mmHg
The cardio cuff is typically inflated to 60–90 mmHg, a level below diastolic blood pressure, to record relative cardiovascular changes without fully occluding arterial flow.
Question 2: Which of the following best describes the role of the baseline calibration check before a polygraph test?
- It confirms the subject is telling the truth
- It verifies instrument channels are functioning and recording properly (Correct answer)
- It establishes the subject's guilt threshold
- It trains the algorithm on the subject's voice
Correct answer: It verifies instrument channels are functioning and recording properly
A pre-test calibration check ensures all instrument channels are operational and recording clean physiological signals before the formal examination begins.
Question 3: In a computerized polygraph system, what does 'gain' refer to?
- The speed at which the chart scrolls
- The sensitivity or amplification of a physiological channel (Correct answer)
- The time interval between questions
- The number of chart runs recorded
Correct answer: The sensitivity or amplification of a physiological channel
Gain is the amplification factor applied to a physiological channel; adjusting gain allows the examiner to optimize the tracing size for accurate visual and algorithmic analysis.
Question 4: What is a 'stim test' (stimulation test) used for in polygraph examinations?
- To stimulate emotional responses with visual imagery
- To demonstrate to the subject that the instrument can detect deception (Correct answer)
- To check the electrical resistance of the GSR sensors
- To measure resting heart rate before questioning
Correct answer: To demonstrate to the subject that the instrument can detect deception
A stimulation test (known number or card test) is used to convince the subject that the polygraph can detect lies, which helps ensure robust physiological responses during the actual examination.
Question 5: Which APA-approved computerized polygraph system uses proprietary algorithms such as OSS-3 for scoring?
- Lafayette LX5000 (Correct answer)
- Limestone Technologies Polysuite
- Axciton Systems
- Stoelting CPS
Correct answer: Lafayette LX5000
The Lafayette LX5000 includes OSS-3 (Objective Scoring System version 3), a validated algorithmic scoring tool used to provide a probabilistic assessment of truthfulness.
Question 6: What is 'chart drive speed' in the context of analog or digital polygraph systems?
- The rate at which the examiner asks questions
- The speed at which physiological data scrolls or is displayed on the chart (Correct answer)
- The refresh rate of the examiner's monitor
- The speed at which data uploads to a central server
Correct answer: The speed at which physiological data scrolls or is displayed on the chart
Chart drive speed refers to how fast the physiological tracings scroll across the display (or paper), with 6 mm/sec being a common standard that allows adequate visualization of responses.
CPE CPE Instrument Technology 2
What is the recommended cuff inflation pressure range for the cardio component during a polygraph examination?