Scientists have proven that anyone can beat a lie detector test if they know how. People from various walks of life took part in the study where they managed to beat modern lie detectors after being instructed how to do it., reducing the accuracy of the recognition techniques.

The science of beating the lie detector

A recent study focused on trustworthiness of brain imaging techniques in modern lie detectors.

It’s been known for a long time that there is a way to beat a traditional lie detector concentrating on physical characteristics such as pulse. Modern machines detecting lying are more sophisticated and thought to be highly reliable.

Dr. Chun-Wei Hsu and Dr. Giorgio Ganis, both working at the University of Plymouth, USA, in cooperation with their colleagues from the University of Padova, Italy, set to check if this was true.

Fake-detecting MRI

Functional magnetic resonance imaging (fMRI) has been used for years to determine whether someone’s statements are true or false.

Its operation is based on measuring brain activity values.

Theoretically, this procedure, which involves complicated technological devices, is quite difficult to beat.

However, a recent study has shown this is an absolutely feasible task provided that a tested person uses several mental countermeasures, which could be easily learned.

The report available in the Human Brain Mapping journal proves that people can confuse the test device if relevant cheating methods are applied.

In this case, accuracy of conclusions provided by the test can quickly drop by 20%.

That said, the study’s authors advise forensic experts to take some preliminary measures prior to running the test to find out whether the client is going to compromise the results.

This has been the first research of its kind focused on mental countermeasures a human brain can oppose to the FMRI technology in uncovering fibs.

fMRI operation is based on measuring brain activity values.

How lie detectors pick  that a person is not telling the truth

Lie detectors, or polygraphs, work on the principle of asking a person a specially designed series of questions, some of which are neutral and others are highly sensitive for a person trying to hide something.

For example, an individual who has stolen a necklace will respond to the word ‘necklace’ in a different way than to other similar words like ‘ring’, ‘diamond’ etc. By noticing and measuring such physiological signs as sweating or heartbeat, the specialist viewing the results is able to filter the truth from the fake.

The countermeasures used by perpetrators leverage the same principle.

Certain techniques allow con artists to get prepared for the test and keep the monitored values under control, thus confusing investigators.

This is why modern methods went further and took to analyze not just physical signs such as pulse but went directly to the brain, recording the changes.

A FMRI device tracks the blood flow to relevant brain areas. A person’s control to suppress certain natural body reactions to mentioning a thing or thought they are trying to hide should not work in this case, it was believed.

The premise is that the brain recognizes a trigger word and produce an involuntary response, which can be noticed as a highlighted brain area on a scan image. Going directly to the brain should remove the issue of tricking the polygraph in known ways.

The experiment

To check whether it was possible for a person to misled the modern polygraph based on MRI, researchers set up an experiment.

Each participant was given an envelope containing a piece of paper with a number they would keep secret.

As a part of the study, 20 participants were taught two methods of misleading the lie detector.

1. Amplification — making the recollection more significant by associating some meaningful memories with the control item.
2. Reduction — concentrating on superficial aspects of the control item as opposed to familiarity of the object, thus making it less important.

Even though participants were ordinary people who didn’t have any training in covering untruths or psychological manipulations, the results of detection tests dropped by 20%.

The FMRI equipment struggled to identify variations in the brain activity, which means people were able to hide their secret numbers successfully.

Amplification — making the recollection more significant by associating some meaningful memories with the control item.

Can anyone confuse lie detecting machines?

As a conclusion, the researchers say the test requires fine tuning to boost robustness.

More specifically, a procedure should be performed prior to running the test to make sure an investigated person does not use any mental countermeasures. If necessary, the whole brain should be screened rather than only the areas of major interest.

According to Dr. Chun-Wei Hsu, a chief researcher, FMRI tests aren’t so widely used by law enforcement bodies as the traditional polygraph. Nevertheless, they provide an important tool that can be successfully used for both forensic and scientific purposes.

While brain imaging provides a more direct monitoring of the thought process, human mind is an incredibly powerful tool, capable of changing natural body’s responses on the deepest levels.

Most of us don’t need to pass sophisticated polygraph tests and have little to hide. That’s always the best way to live life, isn’t it?

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