Lie detectors, now widely used to screen US government personnel, have had their own credibility challenged. A study by the congressional Office of Technology Assessment (OTA) of all available research on the subject has concluded that polygraph (lie detector) tests lack scientific validity.
It warns that such tests, as they are routinely used by the federal government, run a significant risk of falsely labeling innocent people as liars and security risks. Also, it notes that guilty subjects may be able to use such countermeasures as specific physical movements, drugs, hypnotism, biofeedback, or previous experience with polygraphs to deceive the lie detector itself.
Thus the study lays out substantial doubts about the government's increasing use of polygraph tests for screening federal personel for security purposes.
As a think tank which assesses scientific and technological issues for Congress, OTA makes no policy recommendations. At the most, it will lay out possible alternatives for Congress to consider. In this case, it has stopped just short of saying the government should halt routine lie detector screening unless and until substantial new research were to improve its credibility.
OTA notes that ''federal government use of polygraph tests has tripled over the last 10 years.'' About 23,000 tests were given in 1982, vs. 7,000 in 1973.
Most federal agencies use the tests mainly in criminal proceedings. Only the National Security Agency (NSA) - which is responsible for secret codes, communications, and eavesdropping - and the Central Intelligence Agency (CIA) use polygraphs for routine personnel screening. However, OTA points out, NSA accounted for almost half of the total federal testing in 1982.
Now the use of such tests is to be greatly expanded. Summarizing directives issued this year and a Department of Justice policy statement permitting government-wide testing, which was announced Oct. 19, OTA anticipates ''substantially expanded use of the polygraph for purposes of personnel screening. . . .'' That would include screening personnel of companies doing business with the government. Refusal to take such a test could invoke administrative job sanctions against individuals.
OTA reminds Congress that, in 1965 and 1976, ''the House Government Operations Committee concluded that there was not adequate evidence to establish the validity of the polygraph.''
The study report acknowledges that both the NSA and the CIA believe the lie detector is a useful screening tool. It recognizes that a 1980 survey by the director of Central Intelligence Security Committee found the polygraph to be the most productive of all background investigation techniques. But, OTA says, this was a utility study, not a study to determine lie detector validity.
The OTA study found meaningful evidence that lie detectors work only in specific criminal investigations. But it also found that the tests were used only after investigation had identified prime suspects. They were not used for blanket screening.
Even the basic theory underlying lie detector tests is questionable, says OTA. The commonly accepted theory holds that a person fearing detection will exhibit measurable physiological reactions when lying. OTA says such theory is ''only partially developed and researched.''