Netflix has jumped on the bandwagon of reality with several recent posts these days. One of them is Love with surety, a program in which six couples spend three weeks in a villa located in an idyllic setting. To win the prize they just have to tell the truth; something that, supposedly, will not be easy. The reason we’re talking about this in a science article is because, to hunt down liars, the show uses a lie detector that supposedly captures who does not tell the truth through small changes in their eyes and his look.

One wonders if this is possible. If so, why not use it in court to make sure that the testimonials are real? Or in the Congress of Deputies? Well, we are not going to get into the latter, as it would be a tricky subject. But yes in trials.

Really, it is very important to detect that what is said in them is true. If the lie detectors were really effective there is no doubt that they would be used beyond reality shows. The problem is that the scientific evidence does not make them look good. Neither those that are based on the eyes nor any other. Let’s see the reasons.

The pseudoscience that seeks the lie in your eyes

Much of what these eye-based lie detectors measure stands on the foundations of the Neuro-Linguistic Programming. This is neither more nor less than a pseudoscience, devised in the 70s by Richard Bandler, John Grinder and Frank Pocelik. It defends that there is a connection between neurological processes, language and behavior patterns learned through experience.

There are several physiological parameters that are related to the truth or the lie; but, focusing on the eyes, it is often said that people who lie tend to look right, while those who tell the truth wear their eye movements toward the left. All of this, of course, unconsciously.

Neuro-Linguistic Programming is a pseudoscience that, among other things, says that liars look to the right and those who tell the truth to the left.

They are supposed to be almost imperceptible movements, but that could be detected, either with machines, such as the famous lie detectors, or by monitoring a trained eye. The problem is that there is no scientific evidence that this is true.

In fact, in 2012 it was published A study aimed at checking it through three experiments. In the first, the eye movement patterns of people previously known to be telling the truth or lying were coded. No relationship was found with what Neurolinguistic Programming ensures. And not in the second experiment, in which the participants were previously informed about what this pseudoscience affirms. Finally, the third experiment encoded the eye movements of lecturers, with the aim of looking for patterns related to the veracity of their statements. But there was no success either.

Others Eye-related parameters allegedly scanned by lie detectors are the pupil dilation (they are supposed to stretch more when lying) or the response time before a question. However, there are also no well-designed, peer-reviewed scientific studies that can reliably claim that this is effective. As much as realities disguise it as science.

Photo by Tingey Injury Law Firm on Unsplash

What Happens at Lawsuits?

In SpainAs in many other countries, lie detectors or, in general, the analysis of physiological parameters do not serve as proof that a person is giving a more or less real testimony.

It is advisable to collect the statement twice to be able to look for inconsistencies

Generally, interrogations use methods such as Global Assessment System. This must be done by qualified forensic psychologists and consists of several steps. First, a first statement is collected, preferably free speech. That is, the person is left to speak openly about the facts, without questions. Second, the statement is repeated, but this time questions are being asked. So you can check for inconsistencies.

As explained in an article about the topic Ramón Arce and Francisca Fariña, from the Universities of Santiago de Compostela and Vigo respectively, who tells the truth “narrates images, so the description of the events, even though it is very similar, will be of a different construction as it does not respond to episodic schemes.”

Once this part is finished, the statements that have been made throughout the Judicial process. However, it must be taken into account that their value is relative, since they may be transcripts that do not reliably reflect what has been witnessed.

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That is what the rest of the steps are for, such as the analysis of the content of the declarations and the reliability of measurements. Then the statement of the people involved is evaluated and their personality.

Amanda Dakbjorn (Unsplash)

Why isn’t using a lie detector a good idea?

Everything described above may seem complicated compared to a mechanical lie detector. But it is that, in these cases, simplifying as in reality shows is not a good idea. It’s something we’ve talked about in Hypertextual with the forensic psychologistand Marta Perez Angulo. “There is no solid scientific evidence on this subject, although it is true that there are still colleagues interested in introducing these physiological indices as an objective measurer”, he points out. “The reality is that, in practice, there are individuals who would be able to go unnoticed before these meters. As we know in psychology, correlation does not imply causality and falling into these simplifications would be detrimental to science and to our field of study ”.

And precisely for that reason, in his opinion, building a lie detector would be a disaster, which would lead us to have a big bias by different variables.

“On the one hand, we would have people with psychopathic traits who would easily pass the test and who could go unpunished for different crimes. On the opposite side, we would find nervous individuals in the context of a lie detection machine who would end up showing eye movements that for this machine would be the object of suspicion. Ultimately, we would have innocents behind bars and perfect liars on our streets ”.

Marta Pérez Angulo, forensic psychologist

Plus, it’s not just about the eyes. In general, there is no physiological parameters to help us spot a liar. “Any physiological parameter would be susceptible to being biased by different variables and would not be reliable,” says Pérez Angulo. “Sweating is neither more nor less accurate in detecting a lie than rapid blinking of the eyes, because they are not elements that are measurable, although they can be observed by anyone, as would occur with other physiological indices that have commonly been linked to lying. , such as dry lips, swallowing, or a fast heartbeat”.

And why are they used in reality shows?

The fact that in Spain lie detectors or any type of eye analysis are not used in trials does not mean that other countries do not either, as the forensic psychologist also explains. “In Spain we are faithful to scientific method at legal field and it is understood that these pseudoscientific practices are nothing more than a perversion that can create enormous damage to our Legal System. Even with the entire scientific community showing serious doubts about these tests, United States and some Latin American countries they continue to admit these practices as evidence in different judicial processes ”.

And, of course, we cannot leave out reality shows, like Love with surety. This is actually a danger disguised as leisure, because it shows viewers a seemingly simple solution to complicated problems, being able to confuse your perception about what actually happens. It is something that, for Marta Pérez Angulo, is based precisely on the need to want to simplify everything. “The use that is made in these programs of these machines are not more than the reflection of what people would like science to be, pure paraphernalia ”, he opines. “Anyone would love to have a seemingly simple device within reach that allows you to detect if someone is lying, but the reality is quite different.”

Using lie detectors in reality shows can give viewers the wrong idea of ​​the complexity of this type of procedure

And this is applicable to any branch of psychology, not just forensic psychology. “In my opinion, television has participated and continues to actively participate in the perversion of psychology. It cannot be judged that people get the wrong idea of ​​what our job performance consists of, when these characters appear daily on our televisions. It is the responsibility of the different organizations to exercise greater control over these pseudoscientific practices that seriously harm society as a whole and our sector, more specifically ”.

In short, as much as this type of program is paradoxically known as reality TV, we must bear in mind that, most of the time, what they tell it is very far from reality. The final prize is supposed to depend on the results of the lie detector. If this catches in their eyes that they are lying, the money will decrease. It is valued that they tell the truth, but if it is not measured correctly, it is useless. So if we want to watch this show for pure entertainment, that’s fine. But don’t be fooled: whether or not the participants tell the truth is something that no machine could measure.