Lie detectors might work in the movies, but a US congressional report says that when it comes to screening nuclear scientists, you might as well reinstitute the ducking stool.

The US Congressional Research Service last month updated a report looking into the use of polygraphs or "lie detectors" in the US government.

The report specifically focuses on use of polygraph screening in the Department of Energy (DOE), which runs some of America's most sensitive nuclear labs and research programmes.

Large numbers of DOE personnel have been made to take routine polygraph tests since some embarrassing security breaches in the late '90s. These personnel are often highly qualified scientists, which causes some difficulties.

"Scientists do, in fact, represent a particular problem with regard to the administration of polygraphs," says the report. "They are most comfortable when dealing with techniques that are scientifically precise and reliable. The polygraph...does not meet this standard."

The American boffins seemingly don't much care for being examined using a technique they regard as little better than witchcraft.

"The attitude toward polygraphs at the laboratories...runs the gamut from cautiously and rationally negative, to emotionally and irrationally negative," according to the report's author, Alfred Cumming, a specialist in intelligence and security. "Many scientists...are skeptical of its utility."

Cumming frequently cites a highly-critical investigation into polygraph screening by the National Academy of Sciences (NAS). The NAS polygraph-bashers did acknowledge that screening could have some deterrent effect, perhaps putting off the nefariously-inclined from applying for sensitive jobs.

However, they said this deterrent effect would only occur if people believed that polygraphs worked. As most scientists appear not to believe this, there would seem little point in using polygraphs to screen them for employment in the US nuclear programme.

However, polygraphs do have some advocates. Unsurprisingly, these include the American Polygraph Association (APA), "the country's largest association of polygraphers". Strangely enough, the APA says the lack of scientific evidence supporting lie-detector tests is down to limited funding.

Another friend to the polygraph, apparently, is the CIA. The spook agency "cited classified research to support its use of polygraph testing but declined to share its research". Well, it was secret.

"What is not subject to debate and appears to be beyond dispute is that the polygraph does not detect lies," writes Cumming.

Apart from the possibility of doing some serious research, the report concluded that Congress might consider two options for the future of polygraph screening at the DOE. Option one: use the polygraph less. Option two: stop using it altogether. ®