When neuroscience comes to the rescue of justice...


In the 19th century, Cesare Lombroso was the foundation of scientific criminology. He claimed to identify criminals based on the anatomical features of the face and skull. Science came to the rescue of justice... Where are we in the 21st century? The same quest still drives some biologists, especially in the United States where the fight against crime and terrorism is a national priority. Admittedly, vocabulary and methods have changed. We no longer speak of crime but of anti-social psychopathy, while brain imaging has replaced the analysis of the faces and bumps of the skull.

MRI in the courts

lemaroisIn India, the trial of a young woman, Aditi Sharma, made headlines in 2008. Accused of poisoning her fiancé while claiming she was innocent, she was subjected to a lie detector test based on the electrical activity of her brain. The electroencephalogram showed a reaction identical to the sentences "I bought arsenic," "the sky is blue," "I had an affair with Udit. The experts concluded that the purchase of the poison is an established fact as is the colour of the sky. The argument was accepted as incriminating evidence and the girl was sentenced to life imprisonment. Fortunately, the publication of the case in the New York Times as well as numerous challenges to the validity of the test have led to the conviction being quashed. The Supreme Court of India nevertheless upheld the authorization of lie detectors on condition that that the accused gives his or her consent. (Illustration: painting of Fabrice Lemarois)

In the United States, the judicial use of examinations relating to the anatomy and functioning of the brain dates back some twenty years, in connection with the emergence of new brain imaging techniques. One of the first trials of this kind was that of John Hinckley, accused of the attempted assassination of President Ronald Reagan in 1981. The defence presented a CT scan of Hinckley's brain showing an enlargement of the grooves in the cortex, as is sometimes found in some schizophrenics. Although the observation was never confirmed, the argument was successful because Hinckley was found not guilty by reason of insanity.

In the 1990s, University of California neurologist Adrian Raine testified as an expert witness in a rape and murder trial. MRI scans of the defendant's brain showed reduced activity of the prefrontal cortex, which was thought to explain his inability to inhibit his impulses. This allowed him to avoid the death penalty. In 2005, the Supreme Court considered neurobiology in its decision to prohibit the death penalty below the age of 18. The American Psychiatric Association had argued that adolescents would not have total control over their impulsivity and emotions because, according to MRI, their prefrontal cortex is not yet fully mature.

There are 130 trials in the United States in which brain imaging specialists have been called in to enlighten judges and juries about the brain condition of defendants and witnesses. The subject of the legal applications of neuroscience has become a research topic in its own right, known as "Neurolaw". It is the subject of major funding programs involving universities and the American administration.

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In France, to assess the criminal responsibility of an accused, the judge appoints psychiatrists and psychologists who base their expertise primarily on interviews and very little on brain imaging. But for how much longer? The American model tends to impose itself with the prospect of seeing neurosciences replace the clinical doctor in the evaluation of the responsibility and dangerousness of a defendant.

Searching for the brain areas of crime...

brain-justiceViolence, aggressiveness, moral decay, crime, terrorism... Could all these deviant behaviours have their origin in the brain? To find out, the method of choice is MRI imaging, which allows us to see the brain at work, without having to open the skull. The number of publications on these topics is exploding, mainly in the United States. From 70 articles published from 1990 to 2000, the number has risen to 350 from 2000 to 2008.

The laboratory run by Adrian Raine is specialized in the field. Its objective is to study the neural bases of antisocial, aggressive and criminal behaviour "in order to develop new treatments and prevention programmes for these diseases that are very costly to society".
In his 2008 publication, Raine reviews the work on the anatomical particularities of the brains of violent psychopaths.The problem of its interpretation remains. Indeed, to date, no scientific data has been available to establish a causal relationship between a reduction in cortex thickness and deviant behaviour. Because of the plasticity properties of the brain, the origin of variations in the structure of the cortex cannot be determined. MRI of the brain anatomy does not provide any indication of a biological origin of aggressive behaviour.

(1). Several MRI studies have shown a slight reduction in the thickness of the cerebral cortex in the prefrontal and temporal regions. It should be noted that this phenomenon is by no means specific to criminals. It has also been observed in alcoholics, drug addicts and some epileptic patients.

How does the criminal mind work?

electroencephalogram3In an attempt to answer this question, researchers have used functional MRI (fMRI) to analyze the active brain. Several studies have been done among abusive psychopaths who were followed in psychiatric institutions after serving their sentences. (2). Most fMRI tests involved analyzing brain activity in response to the presentation of pictures of faces with different expressions. These pictures were taken from a database commonly used by psychologists, called the International Affective Picture Set. It contains photos that evoke emotions that are classified as positive (couples in love, small dogs, ice cream cones), neutral (house, fork, book) and negative (mutilated bodies, mean dogs, car accident injuries).
The results of these experiments are mixed. Some studies show different activities between psychopaths and witnesses, only when presenting emotionally negative pictures. Other studies show activations regardless of emotional content. In general, variations in activity are localized in the prefrontal cortex and the amygdala. This is not surprising because these regions are mobilized in brain functions that involve a coupling between cognitive and affective processes. They are just as active in the presentation of scenes of unhappiness or happiness, violence or love. It is worth noting that MRI tests take place in laboratory conditions that have nothing to do with the reality of life. Moreover, most experiments are carried out on a small number of subjects, usually between 10 and 40, which makes the results difficult to generalize. So far, there is no solid argument that a brain dysfunction or an anatomical abnormality can be responsible for violent or criminal behaviour.

MRI for better or for worse.


irm-imageA huge step in our knowledge of the brain has been taken with MRI techniques. We now have an exceptional tool that allows us to observe both the structure and function of the living brain. A whole map of regions activated in sensory, motor and cognitive functions has been revealed. The applications in human clinical practice are immense.
Another major contribution of MRI is that it has revealed the extraordinary "plasticity" properties of the brain. (3). We can now see the brain changing in response to learning and experience. For example, in pianists, there is a thickening of the cerebral cortex in the areas that specialize in finger movement, hearing and vision. In addition, these changes are directly proportional to the amount of time spent learning the piano in childhood. Brain plasticity is also at work during adult life. An exemplary case has been described in subjects learning to juggle three balls: after three months of practice, MRI shows a thickening of the regions of the cortex specialized in vision and coordination of the arms and hands. And if training stops, the previously thickened areas regress.

These results clearly show how life events modify brain function, which translates concretely into the restructuring of neuron circuits in the cortex. Nothing is ever fixed in our brain. This is a fundamental concept to consider when interpreting MRI images, including in court cases. Seeing anatomical variations in a brain does not mean that they have been present since birth, nor that they will remain there. MRI provides a snapshot of the state of a person's brain at a given time. It does not provide information about the criminal's motives and thoughts at the time of action. It has no diagnostic or predictive value on the emergence of deviant behaviour.


Another limitation is due to methodological biases in the fabrication of MRI images, with some subjectivity on the part of the experimenters in the choice of analysis software. From the same raw data, opposite results can emerge. Another danger is the power of fascination of coloured images of the brain, which may appear as "objective" scientific evidence to lay judges and juries. Finally, it is important to keep in mind that the majority of antisocial or criminal behaviour is perpetrated by individuals with normal brains. MRI is clearly far from representing the scientific support that some people have been advocating in the practice of justice.

The lie detector business


electroencephalogram2About ten years ago, two American companies, "No lie MRI" and "Cephos Corp. began marketing fMRI-based lie detectors. Their slogans go straight to the point: "Truth is our business": "We offer the only reliable lie detection measure in the history of mankind at 93%. If your word or reputation is in question, contact us for a scientifically validated test.

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These companies offer their services legally to companies for job interviews and to insurance companies for the settlement of disputes. Another promising application is the selection of clients and employees according to their potential to develop brain pathologies. The price of the fMRI test is $4,000. It is based on the assumption that lying requires more effort from the brain than telling the truth, which results in increased activity of the prefrontal cortex.
The principle of the method is questionable to say the least. First of all, the experimental situation of fMRI is necessarily artificial compared to the real world. Furthermore, the activation of the prefrontal cortex is in no way specific to lying. It can be observed in tasks of memorization, anticipation or attention. Finally, the argument of activation of the cortex by lying is only a statistical probability on a sample of people and is not necessarily valid for an individual taken in isolation.

To date, the validity of fMRI to detect lies has not been recognized in the courts. Nevertheless, its use is being considered in the United States in terrorism cases.

The neurophilia epidemic


neurojusticeThe speed with which brain science is creeping into society is striking. Over the past decade or so, the growing impact of neuroscience in cultural representations, education, media, literature, films, etc., has been evident. Neuro" is everywhere: neuroeconomics, neuromarketing, neuroinformatics, neurophilosophy, neuropsychoanalysis, neurotheology, neurogymnastics etc. The field of law has not escaped it with the arrival of neurojustice.

Behind this "neurophilia", which is supposed to explain everything, hides yet another avatar of the ideology of biological reductionism in search of a scientific and indisputable cerebral truth. Combined with the fascination of MRI images of the brain, the neuroscientific argument becomes eminently appealing and convincing to a broad, uninitiated public. In the current French context, which defends a societal logic of the race for certainty and the demand for security, vigilance is essential. At a meeting on this topic organized in 2009 by the Centre d'Analyse Stratégique, Christian Byk, Judge at the Paris Court of Appeal, stated: "The detection desired by certain early warning signs of delinquency in three-year-old children, the choice also to add to the judicial arsenal a preventive security sentence to keep in detention criminals who have served their sentence but are likely to reoffend are recent developments in the debate in French society (...) Finally, screening thanks to neuroscience would be a prediction in the service of judicial eugenics". (4).

The risk is indeed to give MRI the capacity for objectivity and prediction of conduct, with the more or less stated aim of using it to identify individuals who are potentially dangerous to society. This vision of a biological determinism of behaviours that would be pre-cabled in the brain is in total contradiction with scientific advances that show the plasticity of the brain and its capacity for evolution and adaptation throughout life. As the great psychiatrist put it so well Edouard Zarifian : "Imaging research is scientific, but its interpretations are scientific... Seeing the brain think is just a poetic metaphor. We "see" only lists of numbers that come out of the machines and that we transpose with colour codes to represent the silhouette of a brain. Only the subject's words can give access to the content of his or her thoughts. » 



(1) Yang Y et al, Brain abnormalities in antisocial individuals: implications for the law, Behavioral Sciences and the Law, vol 26, 65-83, 2008.
(2) Marsh A. et al, Deficits in facial affect recognition among antisocial populations: a meta-analysis, Neuroscience and Biobehavioral Reviews, vol 32, 454-465, 2008.
(3) Vidal C., Le cerveau évoluue-t-il au cours de la vie, Ed Le Pommier, 2009
(4) Seminar "Scientific and legal perspectives on the use of brain sciences in judicial proceedings", Centre d'Analyse Stratégique, 10 December 2009

Books by Catherine Vidal :

- – « Women and health, another men's business? "Edition Belin, September 2017
- "Our Brains, All the Same All Different! "Edition Belin, September 2015

- "Do girls have brains made for math?" Catherine Vidal, Le Pommier, 2012.
- "Men, women: do we have the same brain? Catherine Vidal, Le Pommier, 2012

- Does the brain evolve over the course of life? "Catherine Vidal, Le Pommier, 2009.
- Nos enfants sous haute surveillance", Sylviane Giampino and Catherine Vidal, Albin Michel, 2009- Brain, Sex and Power", Catherine Vidal and Dorothée Benoit-Browaeys, Belin 2005

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