5 ms·

Certainly. It's not a perfect or fool proof method. Nothing is. It's simply a piece of evidence to look for.

by mankyd 11y ago

learc83 11y ago
That's the problem with this technique. The false positive rate is likely pretty high, and without knowing the prior probability that the person is lying, the technique could be worse than useless.
- mankyd 11y ago
  You would never convict someone of deceit based on any liar-detection methodology. They're simply tools used to warrant further investigation. There will be truth-tellers who fail this test, but you find nothing conviction worthy. They'll be fine. There will be liars who pass this test. Hopefully you catch them later by other means, just as you would have otherwise. And of course, there will be those who pass who are never caught. This tool does not make that any worse.
  - learc83 11y ago
    >This tool does not make that any worse. If the false positive rate is too high and the prior probability a given person being interviewed actually lied, then the test is actively harmful. I.e., if a positive result is more likely a false positive, then you end up wasting investigation resources. In this case you'd have been better off just flipping a coin to decide if someone warranted more investigation. >There will be truth-tellers who fail this test, but you find nothing conviction worthy. They'll be fine. Tell that to all the people who lost jobs, or spent months of their life under investigation because of failed polygraph tests.
    - mankyd 11y ago
      I actually failed my poly - several times :) I should of course mention that not everyone uses these tools correctly. I suppose that could be harmful. But then again, if an investigator is simply looking for a reason to find someone guilty, then the accused is eff'ed either way.
caminante 11y ago
For sure. I assume the detection technique works pretty well, even against "better" liars. That said, I've encountered folks that are so good at being slippery that you almost have to admire their skill.

Certainly. It's not a perfect or fool proof method. Nothing is. It's simply a piece of evidence to look for.

by mankyd 11y ago

Certainly. It's not a perfect or fool proof method. Nothing is. It's simply a piece of evidence to look for.

That's the problem with this technique. The false positive rate is likely pretty high, and without knowing the prior probability that the person is lying, the technique could be worse than useless.

mankyd 11y ago
You would never convict someone of deceit based on any liar-detection methodology. They're simply tools used to warrant further investigation. There will be truth-tellers who fail this test, but you find nothing conviction worthy. They'll be fine. There will be liars who pass this test. Hopefully you catch them later by other means, just as you would have otherwise. And of course, there will be those who pass who are never caught. This tool does not make that any worse.
- learc83 11y ago
  >This tool does not make that any worse. If the false positive rate is too high and the prior probability a given person being interviewed actually lied, then the test is actively harmful. I.e., if a positive result is more likely a false positive, then you end up wasting investigation resources. In this case you'd have been better off just flipping a coin to decide if someone warranted more investigation. >There will be truth-tellers who fail this test, but you find nothing conviction worthy. They'll be fine. Tell that to all the people who lost jobs, or spent months of their life under investigation because of failed polygraph tests.
  - mankyd 11y ago
    I actually failed my poly - several times :) I should of course mention that not everyone uses these tools correctly. I suppose that could be harmful. But then again, if an investigator is simply looking for a reason to find someone guilty, then the accused is eff'ed either way.

caminante 11y ago

For sure. I assume the detection technique works pretty well, even against "better" liars. That said, I've encountered folks that are so good at being slippery that you almost have to admire their skill.