Anon, I am truly amazed at the fact the polygraph is still with us after all these years.  The hypothesis that there are physiological responses exclusively indicative of deception receives just about as much respect from the scientific community as it did in the 1920s:  nearly none.

Despite all the so-called improvements to the procedure such as the computerized polygraph, the whole house of cards still rests on the rickety table of the flawed assumption mentioned above.  Without a valid theory behind it, the computerized polygraph amounts to nothing more than "garbage in, garbage out."

I recently read an interesting article on-line which discussed how nearly all purportedly scientific techniques are both validated and accepted by the scientific community within a couple of generations, or fall by the wayside.  The author was incredulous at the fact that the polygraph is still with us despite the loathing of the scientific community for nearly 90 years.

Unfortunately, I have misplaced the link for this article.  If anyone is aware of where it is located, feel free to post the link on this thread.

1923 
In Frye v. The United States, the U.S. Court 
of Appeals rules against admitting polygraph evidence in court. Expert
 
FRYE v. UNITED STATES  No. 3968
 
Court of Appeals of District of Columbia
 
293 F. 1013; 1923 U.S. App. LEXIS 1712; 
54 App. D.C. 46; 34 A.L.R. 145
 

Just when a scientific principle or 
discovery crosses the line between the 
experimental and demonstrable stages 
is difficult to define.
Somewhere in this twilight zone the 
evidential force of the principle 
must be recognized, and while courts 
will go a long way in admitting expert
testimony deduced from a well-
recognized scientific principle or 
discovery,the thing from which the 
deduction is made must be sufficiently 
established to have gained general 
acceptance in the particular field 
in which it belongs. 
 
We think the systolic blood pressure 
deception test has not yet gained such 
standing and scientific recognition 
among physiological and psychological 
authorities as would justify the courts 
in admitting expert testimony deduced 
from the discovery, development, and 
experiments thus far made.  
--- The judgment is affirmed.