Rapist and serial killer Brian Dugan was a psychopath. At least that is what brain scans presented by his defense attorney seemed to show.

But these detailed fMRI images were not enough to sway the courtroom officials in his favor, although they bought him a few hours’ extra time while the jury deliberated overnight. At the time, Dugan was already serving life sentences for two other murder cases, and on the morning of November 11^th, 2009, he was issued with a death sentence for the rape and murder of 10-year-old Jeanine Nicarico [3].

Steve Greenberg, Dugan’s lead attorney, argued that the criminal’s mental illness should be a “mitigating factor because it impaired his ability to control his behavior” [3]. He stated that although the deviations illustrated through the fMRI images did not justify Dugan’s actions, they provided a potential reason for the crimes and might warrant some leniency from the jury in terms of his sentence.

Similar to the Dugan, many murder suspects in parts of India, Europe, and the United States have sought the aid of neuroscans to prove their possibly abnormal mental state [2]. Even prosecutors have presented such scans for purposes of lie-detection.

However, this rising field of neurolaw has its shortcomings. Ranging from fMRI scans to CT scans to other EEG-based scanning techniques, the use of neuroimages as evidence in courtroom trials has been both controversial and questionable when it comes to accuracy and ethical risks.

The Science Behind Neuroimaging

Neuroimaging is the use of various instrumental techniques to generate images that represent the structure and function of the brain.  The most common method brought to the courtroom is the technique of functional magnetic resonance imaging (fMRI).  As a scanning technique that has been deemed reasonably accurate over the years, the fMRI is a noninvasive procedure that uses a magnet to generate images of changes in blood flow in the brain [1].

On the other hand, the CT scan is an invasive digital processing technique that displays a three-dimensional image from several two-dimensional X-ray images rotated about a central axis. While the fMRI has been proven to be the more sensitive of the two processes, it fails to correctly analyze age and gender of the subject, similar to the CT scan [1].

Assuming impartial and accurate analysis, both processes may provide proof that there is an abnormality in the brain, but the underlying causation that leads to the subject’s actions is absent. In other words, there is no linkage between the cognitive processes and actual behavior of the accused person.  For instance, the case United States vs. Hinckley (1982) tried a man for an attempted assassination of President Ronald Reagan, and the defense presented CT scan evidence. A psychiatrist witness was brought in to testify, who deftly said there was an atrophy in the accused person’s brain that could be linked to schizophrenia [1]. When a radiologist was brought in to validate the interpretation of the images, the abnormality was indeed identified but did not have any direct implications in terms of the sanity of Hinckley. Although there are missing links between interpretation of the data and the actions which they aim to explain, the process in which conclusions are drawn from the scans is inherently subjective.

Speculative in Nature: Real Evidence or Not? 

A certain amount of prejudice is an inherent constituent of any judicial system. However, the range of conclusions that may be drawn based on differing interpretations of these scans may lead to further bias; the question remains to be whether this potential for additional bias is enough to ban the use of such evidence from courtrooms.  

Many experts argue that judging based on apparently structural abnormalities in the brain “oversimplifies the complexity of the crime” (2). Any serious offense cannot be attributed to or explained solely by a series of images that simply show that the accused individual’s mind works differently than others.

Although these distinct scanning methods are theoretically psychological profiling tools, the collected data can often be analyzed in varying ways, leading to clashing conclusions and potentially drastically different verdicts. When it comes to lie-detection by tracking the subject’s memories, experts say that scans can “accurately decode whether people think they remember something, but not whether they actually remember something” (3). Therefore, the scans are only as strong as the person’s memories, and death sentences cannot be issued based on what the suspect believes to have seen or done.  So, can evidence that is based on human recollection ever be free of bias to the extent necessary to be considered trustworthy? If not, then perhaps such scanning technologies may not truly qualify as evidence fit for a courtroom trial.

An Appearance of Reliability

If brain scans are enough to hint that the defendant may be incompetent or insane in any way, the judge and jury may alleviate the nature of the punishment due to feelings of sympathy or pity for the accused.  Studies have shown that when dealing with cases of insanity, or in this case, potential insanity, the jury is more likely to return a verdict of not guilty (1).

The danger with any sort of scientific evidence is that it gives off an air of reliability, so any expert witness who is qualified to present conclusions drawn from the scan will appear  dependable, since no one else is the courtroom is likely to even understand the science behind his or her logic. 

As a result, the jury is often confused and may easily believe the seemingly credible images generated with cutting-edge technology and the latest breakthroughs in neuroscience.

Whether it is feelings of sympathy for a potentially mentally unstable defendant or easily-earned belief in the neuroimages due to their scientific nature, the response of other individuals in the courtroom is vital to the final judgment. In court systems where the jury has a great deal of power over the final verdict, these kinds of subtle psychological effects may lead to drastically diverse decisions. And when it comes to serious cases, there is a significant difference between sentencing someone to death and setting them free as “not guilty,” to the accused, to the victim, and to the rest of society.

A Change Brought About Too Early

Scientific evidence such as neuroscans could possibly be a considerable asset to any judicial system, but the ethical and psychological complications suggest that perhaps the technology is still too young and speculative in nature.

There is still great room for inaccuracy in the scanning methodologies themselves, and the risks involved in terms of potentially creating bias in the minds of the jury deem it to be a questionable change that must be deliberated carefully. 

But although forensic investigative science, specifically the relatively new branch of neurolaw, has its gray areas, it is a field to keep an eye out for. In an era inundated with scientific advancement, the inefficiencies and technical inaccuracies of brain scanning techniques will be overcome soon. But it is the ethical implications, the room for prejudice, the psychological effects, that provide the greatest hindrance to the permanent allowance of neuroscans into courtrooms.

But for now, the verdict of “not guilty” will not be determined by the machines, but by the human beings.

And only time will tell which is better.

About the Author

Paulomi Bhattacharya is a junior at The Harker School. Her hobbies include playing the piano, playing volleyball, and doing scientific research. Paulomi is interested in biochemistry and intends to pursue research in the field of bioengineering in her future years. She has written for the Harker School chapter of The Triple Helix for two years now. In 2010, she joined the staff as an Associate Editor and is now co-Editor-in-Chief.

References

1. Shafi N. Neuroscience and Law: The Evidentiary Value of Brain Imaging. Graduate Student Journal of Psychology, Columbia University [Internet]. 2009 [cited 2011 August 8]; Volume 11: 27-39. Available from http://noelshafi.com/uploads/V11_Article_4__Shafi.pdf

1. Palmer K. National Association of Science Writers [Internet]. [Place unknown]: 2010 February 24 [cited 2011 August 8]. Available from http://www.nasw.org/brain-imaging-courtroom-pretty-pictures-or-hard-evidence

1. Miller G. Huffington Post [Internet]. [Place unknown]: 2009 November 24 [updated 2010 March 28, cited 2011 August 9]. Available from http://www.huffingtonpost.com/2009/11/24/brian-dugan-brain-scan-us_n_369486.html