Re: Does this count as a (failed) polygraph?

[George W. Maschke]

Saidme,

Why do you find my rejection of the use of polygraphy "in light of derogatory information" to be "disheartening?" Do you actually believe that CQT polygraphy has any scientific basis and/or any diagnostic value? If so, you are sadly deluded.

The National Academy of Sciences in fact did not find specific-issue polygraph examinations to have any scientific basis or any incremental validity. I think it's appropriate to re-post here a message I posted earlier in the thread, NAS Polygraph Report:

What the NAS Report Says About the Accuracy of Specific-Incident Polygraph Testing

The following is an excerpt from the conclusions of the NAS polygraph report (p. 214 of the HTML version):

Estimate of Accuracy  Notwithstanding the limitations of the quality of the empirical research and the limited ability to generalize to real-world settings, we conclude that in populations of examinees such as those represented in the polygraph research literature, untrained in countermeasures, specific-incident polygraph tests for event-specific investigations can discriminate lying from truth telling at rates well above chance, though well below perfection. Accuracy may be highly variable across situations. The evidence does not allow any precise quantitative estimate of polygraph accuracy or provide confidence that accuracy is stable across personality types, sociodemographic groups, psychological and medical conditions, examiner and examinee expectancies, or ways of administering the test and selecting questions. In particular, the evidence does not provide confidence that polygraph accuracy is robust against potential countermeasures. There is essentially no evidence on the incremental validity of polygraph testing, that is, its ability to add predictive value to that which can be achieved by other methods.

Note that:

1) This estimate of accuracy does not specify what kind of polygraph tests, e.g., CQT vs. R/I vs. GKT "can discriminate lying from truth telling at rates well above chance."

2) The authors' conclusion that polygraph tests "can discriminate lying from truth telling at rates well above chance" is conditioned upon the subject population being similar to "those represented in the polygraph research literature," that is, ignorant of polygraph procedure and countermeasures. Such ignorance cannot be safely assumed, especially with information on both polygraph procedure and countermeasures readily available via the Internet.

3) If the authors' conclusion that "the evidence does not allow any precise quantitative estimate of polygraph accuracy..." is correct, then it (a fortiori) follows that software algorithms peddled by polygraph manufacturers such as Axciton and Stoelting that purport to determine with mathematical precision the probability that a particular individual is lying or telling the truth are worthless.

4) The authors conclude that "the evidence does not provide confidence that polygraph accuracy is robust against potential countermeasures."  It is not safe to assume that anyone passing a polygraph "test" has told the truth.

5) The last sentence of the above-cited paragraph is the key one with regard to polygraph validity (as opposed to accuracy): "There is essentially no evidence on the incremental validity of polygraph testing, that is, its ability to add predictive value to that which can be achieved by other methods." What this means is that there is no evidence that polygraph "testing" provides greater predictive value than, say, interrogating a subject without the use of a polygraph, or with a colander-wired-to-a-photocopier that is represented to the subject as being a lie detector.

The NAS's conlusion that "specific-incident polygraph tests for event-specific investigations can discriminate lying from truth telling at rates well above chance, though well below perfection" with naive subject populations is hardly a vindication for the validity of CQT polygraphy, and those in the polygraph community are formally cautioned against publicly misrepresenting it as such, as you can expect to be publicly called out on it.

[Saidme]

George

You wrote:  2) The authors' conclusion that polygraph tests "can discriminate lying from truth telling at rates well above chance" is conditioned upon the subject population being similar to "those represented in the polygraph research literature," that is, ignorant of polygraph procedure and countermeasures. Such ignorance cannot be safely assumed, especially with information on both polygraph procedure and countermeasures readily available via the Internet.

I disagree with that assertion.  Just because someone reads something on the internet (your stuff or anyone else's) does not make them less susceptible to responding to polygraph.  In my opinion it makes them more susceptible based on their psychological state when they enter the room.

Your wrote further:  3) If the authors' conclusion that "the evidence does not allow any precise quantitative estimate of polygraph accuracy..." is correct, then it (a fortiori) follows that software algorithms peddled by polygraph manufacturers such as Axciton and Stoelting that purport to determine with mathematical precision the probability that a particular individual is lying or telling the truth are worthless.

I concur.  Those algorithms are garbage.

You wrote further still:  4) The authors conclude that "the evidence does not provide confidence that polygraph accuracy is robust against potential countermeasures."  It is not safe to assume that anyone passing a polygraph "test" has told the truth.

What a tap dance that BS is.  "Does not provide confidence".  What kind of crap is that.

And finally:  Did you write this or was this part of NAS's report?

The NAS's conlusion that "specific-incident polygraph tests for event-specific investigations can discriminate lying from truth telling at rates well above chance, though well below perfection" with naive subject populations is hardly a vindication for the validity of CQT polygraphy, and those in the polygraph community are formally cautioned against publicly misrepresenting it as such, as you can expect to be publicly called out on it.

I was just wondering if you were putting your spin on this.

[Skeptic]

George

You wrote:  2) The authors' conclusion that polygraph tests "can discriminate lying from truth telling at rates well above chance" is conditioned upon the subject population being similar to "those represented in the polygraph research literature," that is, ignorant of polygraph procedure and countermeasures. Such ignorance cannot be safely assumed, especially with information on both polygraph procedure and countermeasures readily available via the Internet.

I disagree with that assertion.  Just because someone reads something on the internet (your stuff or anyone else's) does not make them less susceptible to responding to polygraph.  In my opinion it makes them more susceptible based on their psychological state when they enter the room.

Be that as it may (I'm not sure why you'd think that knowing about the trickery and suggestion upon which the polygraph depends would make someone more susceptible to such; perhaps you could explain further), the fact remains that the conditions upon which the NAS reviewed specific-issue criminal testing are not realistic; therefore, deriving the notion that any sort of validity has been shown for such testing from the NAS report is at best a dubious venture.

You wrote further still:  4) The authors conclude that "the evidence does not provide confidence that polygraph accuracy is robust against potential countermeasures."  It is not safe to assume that anyone passing a polygraph "test" has told the truth.

What a tap dance that BS is.  "Does not provide confidence".  What kind of crap is that.

I think it's fairly evident: another way of putting it would be that there's little solid evidence that countermeasures can, themselves, be countered (e.g. detected and compensated for).

In other words, the claims of polygraphers that countermeasures can be detected remain just that: unverified claims (much like the claims of psychics and faith healers).

Skeptic

[George W. Maschke]

Saidme,

You write:

I disagree with that assertion.  Just because someone reads something on the internet (your stuff or anyone else's) does not make them less susceptible to responding to polygraph.  In my opinion it makes them more susceptible based on their psychological state when they enter the room.

Could you explain the basis for your opinion? Let's suppose someone facing a polygraph examination stops by AntiPolygraph.org, downloads TLBTLD, and reads Chapter 3. He/she now understands the trickery behind the "test," including that:

• the "stim" test is just a gimmick intended to dupe him/her into believing that the polygraph can actually detect lies;
• he/she is secretly expected to be less than truthful in answering the "control" questions;
• the irrelevant questions don't actually serve as any kind of "baseline for truth" at all, and are in fact not scored;
• the polygrapher will lie to and attempt to deceive him/her about the above points.

On what basis would you expect a truthful/innocent person so informed to react more strongly to the "control" questions than to the relevant questions?

On what basis would you expect a deceptive/guilty person so informed be "more susceptible" as a result of his/her knowledge?

Regarding the NAS's conclusion that "the evidence does not provide confidence that polygraph accuracy is robust against potential countermeasures" you write:

What a tap dance that BS is.  "Does not provide confidence".  What kind of crap is that.

Your above rebuttal is less than compelling. You may honestly believe that you and other polygraphers have the ability to reliably detect countermeasures. But the scientific evidence reviewed by the National Academy of Sciences does not support any such belief. On the other hand, the evidence does suggest that polygraphy is vulnerable to countermeasures. The NAS report discusses countermeasures in greater detail beginning at p. 139.

You also ask:

And finally:  Did you write this or was this part of NAS's report?

If you re-read my above post, I think you will find that I have made it abundantly clear which portions are quoted from the NAS report and which are my own.

I note that you chose not to comment on the 5th point of my above post (regarding the lack of any evidence regarding the incremental validity of polygraphy).