3 ms·

I’m not going to vigorously defend polygraphs, but I’ll play Devil’s advocate for a bit. From your the Salon piece you linked to, “In studies, polygraph diagnos

by parsimo2010 6y ago

I’m not going to vigorously defend polygraphs, but I’ll play Devil’s advocate for a bit. From your the Salon piece you linked to, “In studies, polygraph diagnoses are often wrong, with rates hovering around 80 percent correct” Which to some people sounds terrible. I certainly wouldn’t want to hang a murder conviction on something with a 20 percent error rate. But on the other hand, 80 percent is better than all but one of the cited results from the Atlantic article, and beats the results from all experiments using untrained people. These con artists are, at best, performing on par with specific lie detection training. Maybe the equipment is just for show, but who’s to say that further biometric measurements, such as functional MRI, wouldn’t significantly increase the accuracy of biometric lie detection (still technically within the realm of nonverbal cues from the Atlantic article)? I don’t think it could be 100% accurate, but I can reasonably see future polygraphs being legitimate tools for lie detection. I wouldn’t want my murder conviction to hang on the results of a current polygraph, but I would be satisfied using one to catch an office supply thief. Well, except it would probably be cheaper to just let someone keep stealing supplies than to pay $8k per employee to administer the tests.

clouddrover 6y ago
> Maybe the equipment is just for show Yes, it's a con. > but who’s to say that further biometric measurements, such as functional MRI, wouldn’t significantly increase the accuracy of biometric lie detection That isn't what they're doing. The "who" that will say it is actual, statistically significant evidence that it works.
nonameiguess 6y ago
The US government still requires polygraphs as a condition of having administrative access to classified systems. They're one data point of many, since you already have a clearance and were thoroughly investigated by other means, but this is an obvious area where it is acceptable to use shitty evidence. The cost of a false negative is extremely high, but the cost of a false positive is close to nothing. Any person who can't pass just has to get a different job. Courts are the exact opposite situation and I hope the practice of using polygraphs in criminal investigations disappears at some point. People tend to miss that the error rate in a diagnostic procedure is not enough to evaluate the usefulness of a procedure because you need the relative cost of different types of error as well. It's the same reason FAANGs can get away with shitty interview methods. Cost of false negatives is much higher than cost of false positives.

clouddrover 6y ago

> Maybe the equipment is just for show Yes, it's a con. > but who’s to say that further biometric measurements, such as functional MRI, wouldn’t significantly increase the accuracy of biometric lie detection That isn't what they're doing. The "who" that will say it is actual, statistically significant evidence that it works.

nonameiguess 6y ago

The US government still requires polygraphs as a condition of having administrative access to classified systems. They're one data point of many, since you already have a clearance and were thoroughly investigated by other means, but this is an obvious area where it is acceptable to use shitty evidence. The cost of a false negative is extremely high, but the cost of a false positive is close to nothing. Any person who can't pass just has to get a different job. Courts are the exact opposite situation and I hope the practice of using polygraphs in criminal investigations disappears at some point. People tend to miss that the error rate in a diagnostic procedure is not enough to evaluate the usefulness of a procedure because you need the relative cost of different types of error as well. It's the same reason FAANGs can get away with shitty interview methods. Cost of false negatives is much higher than cost of false positives.