Opinion: Science in the Courtroom

Should biological explanations for criminal behavior influence a judge’s or jury’s decision about how to handle a case? If so, how?

By | November 6, 2012

An original Victorian Courtrooms at the Galleries of Justice Museumin Nottingham, EnglandWikimedia, FayerollinsonScientific evidence concerning the biological causes of bad behavior is becoming increasingly common in the courtroom. Forensic psychiatrists at Vanderbilt University have genetically screened defendants charged with first-degree murder for a gene associated with antisocial personality disorder, for example. And when it came time to sentence convicted murderer Brian Dugan, neuroscientists performed neuroimaging on Dugan's brain in order to claim he has a defective, psychopathic brain.

What would you do if you were faced with such a decision? Imagine you're a juror tasked with the job of recommending a sentence for a criminal found guilty of aggravated battery. The criminal, Jonathan Donahue, went into a Burger King restaurant with the hope of robbing it, then beat the manager so severely that he sustained brain damage. After he was arrested, Donahue seemed to revel in his crime, even going so far as to have a king's crown tattooed on his back. 

At the sentencing hearing, a psychiatrist provides expert testimony saying that Donahue is a diagnosed psychopath. She explains that psychopathy is a clinical diagnosis defined by impulsivity, lack of empathy, and lack of remorse. The judge tells you that the standard sentence for cases of aggravated battery is about 9 years.

First Question: With this information, how many years in prison will you recommend for Donahue?

There's one more expert witness. This one is a neurobiologist, and he tells you that Donahue has a particular gene that contributes to atypical brain development. Specifically, the part of Donahue's brain that controls his violence-inhibition mechanism is damaged. In normal humans, the violence-inhibition mechanism automatically creates anxiety when they recognize that other humans are in pain or distress. Psychopaths, like Donahue, lack a normal violence-inhibition mechanism.

Second Question: In light of this additional neurobiological evidence, how many years in prison will you recommend for Donahue?

How did you answer the Second Question relative to the First Question? If you increased Donahue's sentence, you probably did so because you interpreted the neurobiological evidence as suggesting his biological constitution makes him a continued threat to society. On the other hand, if you decreased Donahue's sentence, you probably did so because you interpreted the neurobiological evidence as suggesting his biological constitution makes him less responsible for his actions. Or, you could have dismissed the neurobiological evidence entirely and recommended the exact same sentence.

This is the double-edged sword of the science of criminal behavior. The exact same evidence could either increase or decrease punishment, depending on how that evidence is interpreted. 

With scientific evidence about the causes of criminal behavior becoming more and more common in the court room, the legal system faces a pressing question: Which way will the double-edged sword cut? In Dugan’s murder case, a jury ultimately sentenced Dugan to death, but according to his attorney the scientific evidence switched a slam dunk case against Dugan into a much more complicated decision for the jurors. To investigate this question in a systematic way, my colleagues and I performed a national experiment involving US state trial court judges. We presented the judges with Donahue's case and asked them to sentence him. The results of this experiment were published last month in Science. The judges told us that on average they sentenced convicts guilty of aggravated battery to about 9 years in prison. The judges who received only expert testimony concerning Donahue's diagnosis of psychopathy sentenced him on average to almost 14 years in prison. But the judges who received the expert testimony concerning Donahue's diagnosis of psychopathy as well as the evidence concerning the neurobiological causes of his psychopathy sentenced him on average to about 13 years in prison. Compared to just the diagnosis of psychopathy, that is, the neurobiological evidence reduced Donahue's sentence by roughly a year (a statistically significant difference). 

So, our study suggests which way the double-edged sword might cut—towards slightly shorter sentences. But there is another pressing question, one at the intersection of science, philosophy, and the law: Which way should the double-edged sword cut?

The presence of scientific evidence about the causes of criminal behavior is only likely to increase in the courtroom. As a result, scientists and non-scientists alike need to discuss this issue and decide how biological knowledge should influence the legal system.

To get the conversation going, in the Comments section below, list your answers to the First and Second Questions and explain your justification for the increase, decrease, or lack of any change in the prison sentence that you recommended for Donahue.  

James Tabery is a professor of philosophy at the University of Utah.

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Avatar of: TallySkeptic


Posts: 4

November 8, 2012

I would answer "9 years in prison" to both of the author's questions.  For me the main purposes of imprisonment are to 1) protect the public for some period of time, 2) serve as a warning to the public about what could happen to anyone who committed the same crime, 3) enable revenge by proxy for the victim, her family, and friends,  4) provide an opportunity to study the offender,  5) provide an opportunity to "fix" the offender.  While the offender is in prison, experts can try to determine what were the causes of the criminal behavior and implement various programs to correct those causes.  The sentence of capital punishment, however, should be eliminated.

Avatar of: Madmacks


Posts: 1

November 8, 2012


The implications of modifying sentences based on psychopathy is a slippery slope.  The modification of the sentence would be based on science's ability to predict his possibilty for reform or recidivism, or predicting his future behavior.  If Psychopathy is accepted by the Court as grounds for modifying sentencing, then doesn't it also become grounds for predicting the behavior of other litigants before the Court?

The patterns of behavior of psychopaths are uniquely characteristic and evidence of these patterns either exists or does not exist.  The condition impacts the lives of the psychopath and the people around them, so its not hard to rule in or out.  So, shouldn't psychopathy also be considered by Judges in 'high-conflict' divorces, where one parent is out to punish or destroy the other parent?  Psychopathy could also be considered by Judges in cases of fraud, embezellment or other 'white collar' felonies.  Psychopathy is also a seen in children as young as 5.   Perhaps the Juvenile Courts should do more to screen the 'at-risk' youths for psychopathy.

Based on my experience in Civil Court, Judges do not wish to touch the issue of psychopathy.  I have seen psychological experts, lawyers and  judges completely ignore undeniable patterns of behavior consistent with psychopathy, in order to avoid having to address the issue in Court.  

Psychopathy is a pandora's box for the legal system that it is fighting hard to keep closed.

Avatar of: ThinkAboutIt


Posts: 1

November 8, 2012

This is truly distressing to contemplate. The best sentence I can think of is to remand the criminal to an institution where he will be cared for, yet locked away so he will not be a threat to others.


Should there first be the penalty of a jail sentence? This would be discretionary. If the subject is able to understand the difference between right and wrong, he should be held responsible for his actions and meted out the standard punishment, whether he is able to feel his victim's pain or not. Lack or empathy is one thing; ability to understand rules is another.

Avatar of: Devin Camenares

Devin Camenares

Posts: 1

November 8, 2012

At first blush, I would say that the way the sword cuts will reflect what the purpose of detention in prison is.

If placing a criminal in a prison cell is done primarily to punish evil and simply serve justice, then the genetic basis should remove, at most, a slight amount of responsiblity. Therefore a reduction in time served would be called for. 

If the prison time is intended to remove a harmful criminal from society, and hopefully lead to the rehibiliation of this criminal, then clearly evidence for a partially genetic cause for their actions should led to an extended prison sentence.

The article already points this out, but I would add that the first is more abstract, and the latter is related to more practical concerns. I subscribe to the latter interpetation, since I usually favor the practical over the abstract.

After all, notions of justice, responsiblity, and fairness to the criminal (in my opinion) are hard to appreciate when the streets are made more dangerous.

November 8, 2012

Crime and punishment are actions always committed in relation to society at large. The intent of the law is to keep an ordered society with the aim of working towards a betterment of society for all.

With this in mind, we must consider the criminal and the punishment so given.

Criminal acitivity is committed under all sorts of circumstances; there is the poor citizen in need of some goods; there is the jealous wife who would prefer the other woman to no longer exist; there is the greedy investment banker who would like to see a different bottom line; there is the psychopath who likes to shatter someone's skull.

All criminal activity is by deviant behaviour expressed in accordance with good societal practices. Why would it make a difference if we can now scan the brain of a psychopath and figure out that the pathways within his or her brain no longer line up properly? Perhaps a person is poor because some neurons are fired incorrectly. Perhaps a jealous or greedy person has some major misfirings going on within his or her brain also.

Of course, it could be said that the psychopath cimmits a crime for the sheer excitement of it all, but nonetheless, such is considered a malfunction of the brain in connection to the wider workings of a society at large - such behaviour is impossible to tolerate when working towards the societal betterment for ALL.

Just because scientific methods are easier applied when scanning the brain of a psychopath, presumably because such scan would show obvious malfunctions, that does not mean that the poor person, or the jealous person, or the greedy person does not inhibit some sort of shortcomings vis-a-vis proper societal interactions; low intelligence, jealousy and greed are all shortcomings when considered within the larger  picture of proper societal interactions.

Prisons and prison senctences are there for several reasons: to protect society at large from harm's way; to let the criminal bear the burden of responsibility; and to set precedent.

Prison settings should be as such that the criminal of any kind is helped while being incarcerated. The best help any prison setting can offer is for the criminal to find a corrected sense of self within a structured setting. By means of daily work activities, learning activities and social interactive activities(to mention just a few) the incarcerated criminal may find a corrected sense of self. 

It could very well be that the psychopath will never find a corrected sense of self no matter how long the prison sentence would be. Such continued psychopathic behaviour would then be considered unworthy of participating within a free and open society, and the psychopath would be locked up for life.

The laws already make a clear distinction between murder one, murder two, manslaugher etc. The same goes for theft - petty theft, robbery etc. And so forth. The law makes distinctions between all sorts of crimes being committed.

It should make no difference whether the psychopath's brain can show misfirings within the brain since all deviant behaviour is in essence due to the improper understanding of societal well being. And all of our human understandings originate within the functions of the brain.

Therefore no exceptions should be made in any case.



Avatar of: jtrott


Posts: 10

November 8, 2012

First question: 20 years because he almost killed the guy and left him permanently brain damaged.

Second question: death penalty.  A genetically confirmed psychopath has no chance of rehabilitation and will end up killing people.

Avatar of: Hugh-F-61


Posts: 69

November 12, 2012

The first info describes the symptoms, the effect, the second the cause. They say the same thing, he is incurable. Sentence: the same, liftime confinement in a hospital for the dangerously insane, for the protection of others. I would not want to be responsible for the life he destroys if he is ever released.

Avatar of: Roy Niles

Roy Niles

Posts: 115

November 16, 2012

The less responsible you are for your actions, the more time, perhaps, you should be segregrated from a self regulated society and placed under other regultaed supervision.  But of course we aren't philisophicallt prepared to do that.

We have an adversarial justice system in the US which in the end reuires each side's representatives to lie for justice.  Responsibility becomes only incidental to the question of who wins the liars contest.

Avatar of: Cheaptrx


Posts: 47

December 17, 2012

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Avatar of: kandi


Posts: 3

January 23, 2015

I would not agree with prison period. In other hand I would highly suggest this individual have a support of professionals to help him understand his condition. In doing so he will better and eventually understand he is not dysfuctionaly emotional but genetically incapacitated and required physicological attention.

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