A polygraph, commonly referred to as a lie detector test, is a device used to measure an individual’s physiological responses to questions in an attempt to determine the truthfulness of their answers. Though polygraphs boast an accuracy rate of 80% to 90%, false positives remain a significant concern, which is why many courts do not admit polygraph results as evidence. This article delves into the potential reasons behind these false positives.
Machine Error
Like all machines, polygraphs can malfunction or produce errors. They monitor various physiological changes like heart rate, blood pressure, and sweating. Any discrepancy in these readings due to machine malfunction can misrepresent an individual’s truthfulness. However, during the pretest or calibration phase, experienced examiners can often detect machine errors.
Key Causes for False Positives
1. Blood Pressure: High blood pressure or hypertension can affect the readings. Examiners must be informed about an individual’s hypertension so they can adjust their interpretation of the results.
2. Nervousness: Feeling anxious during a test can elevate physiological responses, making an innocent person appear deceitful. It’s crucial for the examiner to differentiate between nervousness and dishonesty.
3. Medications/Drugs: Some drugs, whether prescription or illegal, can affect a person’s physiological responses. Drugs for anxiety or hypertension, for example, might affect heart rate or blood pressure, potentially skewing results.
4. Pregnancy: Pregnancy increases a woman’s blood volume and heart rate, potentially causing elevated readings.
5. Illness: Being sick or on medication for illnesses can distort the readings. Moreover, coughing or sneezing during the test can affect the results.
6. Fatigue: Tiredness or sleep deprivation can cause elevated physiological responses. Therefore, individuals who haven’t rested well might get inaccurate results.
7. Incompetent Examiner: The expertise of the polygraph examiner is crucial. Mistakes during the pretest, insufficient preparation, or misinterpretation of results can lead to false positives.
Rectifying Errors
If you believe an error occurred during your polygraph test, you have several options:
- Request a Retest: Especially if you believe external factors like illness or mindset skewed the initial results.
- Seek a Second Opinion: Have an independent examiner review the records. The aim is to acquire what’s termed a ‘negative assurance.’
- File a Complaint: If you suspect the examiner was at fault, consider lodging a complaint with the appropriate agency.
In conclusion, while polygraphs can be a valuable tool in discerning truth, various factors can lead to false positives. Being aware of these factors and ensuring you’re in the best physical and mental state, paired with an experienced examiner, can help in achieving more accurate results.
