The Pentagon is requesting $30.3 million for a five-year programme to upgrade lie detection technology. The Department of Defense budget document, released for Fiscal Year 2027, outlines a project named “Polygraph+” or “Polygraph Next”. This initiative aims to improve scoring algorithms using artificial intelligence and machine learning. It also targets a method called “standoff sensing”, which allows physiological readings to be taken without attaching devices to the subject.
Details first reported by Inside Defense state the goal is to modernise federal polygraph and credibility assessment tools. Kyri Kotsoglou, a professor at Northumbria Law School, calls the effort misguided. She argues it attempts to reduce a complex issue to something tangible.
The push coincides with heightened tension inside the Department of Defense. Under Defense Secretary Pete Hegseth, the Pentagon has increasingly used polygraph tests to identify sources of alleged leaks. In September, the New York Times reported around 50 officers on the Joint Staff were tested after news coverage highlighted depleted US weapons stockpiles in the war with Iran.
Polygraph+ will be managed by the Defense Counterintelligence and Security Agency (DCSA). The agency conducts background checks for the federal government. The budget document notes the technology will vet prospective employees and detect insider threats. Congress has not yet approved the spending plan. The DCSA did not comment when asked for specifics on the technologies involved.
Previous attempts by the Defense Innovation Unit (DIU) offer potential clues. In 2023, the DIU ran an open submission process to find products for deception detection. It selected two companies to build prototypes: Presage Technologies and Altec Research. Presage claims to measure heart rate and breathing using standard cameras. Altec, a medical sensor company, is branching into non-contact sensing. A screenshot of Altec’s prototype shows it tracks head movement, facial skin temperature, and pore activity. Neither company nor the DIU responded to requests for comment.
Current polygraph technology has barely changed since the device was invented in the 1920s. Examiners rely on blood pressure, pulse, breathing, and sweat measurements. They judge the veracity of replies based on differences in physiological response to baseline questions like “Is the sky blue?” and target questions like “Have you ever committed a crime?”.
The federal government conducts tens of thousands of these tests annually while screening employees. The polygraph has been repeatedly debunked and its results are rarely admissible in court. In 1983, Congress’s Office of Technology Assessment concluded there was very limited evidence supporting the polygraph’s use for screening employees. In 2003, the US National Research Council said evidence on its efficacy was “weak at best”.
Research suggests humans can spot a lie just over half the time without technical assistance. The American Polygraph Association claims the polygraph is between 80 and 94% accurate. However, the 2003 NRC report noted that a screening test with this level of accuracy could still lead to many mistakes. The DoD employs 2.8 million staff. An imperfect system applied at that scale could falsely accuse tens of thousands of people.
Other issues exist too. Polygraph interpretations are often subjective. Different examiners get wildly different results. People from minority groups are more likely to be judged as deceptive. With training, interviewees can learn countermeasures to beat the test. Most commonly, they artificially heighten their body’s physiological response to baseline questions by stepping on a pin hidden in their shoe.
“If you know how it works, you can beat it,” says Sophie van der Zee, an associate professor who studies deception at Erasmus University in Rotterdam. She says the machine’s biggest effect is deterrence. Often, subjects confess before it even begins. But that only works if people think a polygraph works.
Attempts to build new types of lie detectors have occurred over the decades. These ranged from thermal cameras to pupil trackers to brain scans. None have yielded reliable results outside the lab. The problem is structural: there is no single telltale sign of lying that is true for everyone all the time. “There is still no Pinocchio’s nose,” says van der Zee.
AI could theoretically improve polygraphs if it could find patterns in the data that examiners cannot. AI algorithms are more likely to be used for “multi-modal” deception detection. This seeks to combine multiple measurements to create an overall deception score that is harder for people to game. Van der Zee says there are three things happening under the surface that lie detection tries to zone in on: physiological stress, cognitive load, and the conscious efforts people make to conceal the fact that they are lying. Current polygraph technology only tackles one.
“The more you can have combined methods that approach it from these three different angles, the more successful you will be,” van der Zee says. This is not a new concept. In the 2000s, Manchester Metropolitan University researchers developed a system called “Silent Talker”. It generated a deception score from video footage and was later folded into iBorderCtrl, an EU-funded pilot program. In the US, a project called AVATAR combined eye-tracking, voice analysis and body movement detection for use at border crossings. All of these projects have quietly faded away.
Kotsoglou says combining AI and the polygraph is “the worst of both worlds”. She argues it adds uncertainty on top of invalidity. Even if AI or machine learning can spot previously unseen patterns in physiological data, it will not be able to reliably link them to lying because of a lack of ground truth.
“Even if you have all the records in the world from polygraph tests, you don’t know whether those polygraph tests are right or not,” says Marion Oswald, a professor of law who has written with Kotsoglou on the use of polygraphs in the justice system. She fears new forms of lie detection will be used more as a psychological prop than a scientific tool.
“It seems very much a response to the concern of the current administration to leaks and perceived lack of loyalty,” says Oswald. “[Lie detection is] being used as a threat, to intimidate and force people to confess to things, as opposed to anything that’s actually getting valid information.”
