Five Reasons Neuroscience is not Ready for the Courtroom

Neuroscience is nearing dangerous territory, though not because neuroscientists are eager to drive it there. Rather, voices from outside the lab are getting louder in their demands that this fledgling discipline start delivering results that will serve the interests of justice.

The results orbit around what I’m going to call “brain disclosure,” which includes knowing if someone is lying (beyond what the antiquated polygraph can tell us), knowing if someone intended to commit a crime, and knowing if someone will commit a future crime.  You’ll note that the operative word in all cases is “knowing,” because that’s the conventional assumption about the promise of neuroscience: it will reveal the truth.

That assumption is false, and worse, it’s dangerous. The rush to pull tools of neuroscience–most prominently, fMRI scans–into the courtroom where they will stand alongside DNA as a means to disclose the truth is as ill-conceived as it is fanciful.  This urgency, typically spawned by people far removed from the science behind the hoopla, is in need of deflation, and fast. Here are five reasons why.

1.  History tells us that jumping to “scientific” conclusions without a satisfactory basis never ends well. Remember phrenology? How would you like to have been on trial for your life while a phrenologist explained to the jury how the contours of your skull prove that you are an aggressive malcontent capable of murder? Granted, neuroscience is not phrenology, not in the least. But, it is a science in its infancy, and attempting to leverage its tools to produce credible outcomes in court isn’t far removed from the quackery phrenologists passed off as science.

2. Neuroscientists do not agree on the usefulness of fMRI.  Science, in any state of maturity, grows from healthy debate about theory, methods, tools and outcomes. Right now, neuroscience is benefiting from debate among neuroscientists about what fMRI scans can really tell us about how the brain works.  This process is necessary, and it may go on for years as the technology changes and improves. Attempting to pull from this debate solid conclusions that can be used in a courtroom is premature to say the least. The cake is simply not ready, and may not be for some time.

3. We have yet to address the ethical dimensions of courtroom neuroscience. Even if the cake was ready, are we really ready to eat it? If we knew that fMRI, or a future version of the technology, could reveal within four percentage points the likelihood that someone intended to commit murder, would that be good enough to exact justice? How will we recalibrate reasonable doubt in light of a percentage likelihood of thought leading to behavior? I don’t think we have even started to address these questions, and until we do, bringing neuroscience into the courtroom is flatly unethical.

4. Psychological theories are hotly debated in court, so why do we think neuroscience is above reproach? As I was reminded from reading a post by my friend Vaughan at Mind Hacks, neuroscience in its current form is the caboose to the psychology engine, not the other way around. Neuroscience studies typically plug into established psychological concepts (for example, finding the areas of the brain that correlate with decision-making—a very old, very rich study target of psychologists). At best, neuroscience can “flesh out” psychological concepts, but we are a long way from neuroscientific findings trumping psychology in court or anywhere else.  And I would argue that we’re still far away from “knowing” anything solid about how the brain works via fMRI. What we have are correlations and possible linkages, and the interpretation of those is at the center of massive debate (see point #2).

5.  fMRI is not analogous to DNA. I’m hearing this misleading comparison more and more. Comparing the workings of the brain to DNA analysis is like comparing multivariable calculus to elementary algebra. Which is not to say that the science of DNA is “simple” (because obviously it’s not), but it is relatively more clear cut than delving into the vast and ambiguous dynamics of thought.  Not to mention, credible courtroom DNA didn’t appear overnight, and certainly not without lengthy debate and controversy. Bottom line, DNA analysis is an altogether different beast than fMRI, and no comparison should be made between them in support of hoisting fMRI into the courtroom. They shouldn’t even be mentioned in the same sentence.