The connection between criminal justice and brain chemistry can sometimes seem like science fiction, but it’s very much a part of the court system today. In 2015, Fordham established the Neuroscience and Law Center, to explore how advances in neuroscience have prompted the legal profession to question long-held notions about criminal culpability, free will, thought, behavior, and pain.

Deborah Denno, the center’s director and the Arthur A. McGivney Professor of Law, recently sat down to talk about her work with the center.

Full transcript below:

Deborah Denno: When we’re talking about future dangerousness, it has to be put into a situation where people can understand why that person appears to be a future danger. It’s not because a juror is necessarily reacting so negatively to this evidence. It’s because it’s been so poorly introduced into court that it’s sort of a gift for the prosecutor.

Patrick Verel: In 2002, the film Minority Report presented a future in which crime has been completely eliminated, thanks to the ability of authorities to predict in advance who will commit a crime. Now, that film was set in the year 2054. Its premise is still fantastical and absurd, but the connection between criminal justice and brain chemistry is not science fiction. In 2015, Fordham established the Neuroscience and Law Center to explore how advances in neuroscience had prompted the legal profession to question long held notions of criminal culpability, free will, thought, behavior, and pain.

Deborah Denno, the center’s founding director and professor of law, recently sat down with us to talk about her work and the center. I’m Patrick Verel, and this is Fordham News. You recently said that you’ve been to conferences where people have said things like when neuroscience gets fully integrated into the court system, which is silly because it’s already in the courts, when would you say that this practice first started?

DD: We don’t know exactly when it first started, but we do know that it started probably in the 80s when some of this modern neuro imaging was starting to come into place. For example, in the John Hinckley case, a PET scan was used then. Hinckley was accused of attempting to assassinate Ronald Reagan. It was a case that captivated the country. A lot of investigation was made of his background, including the fact that this brain may not be the same as a normal brain.

PV: Now, your center is currently studying every criminal case in the United States that has used neuroscience in any capacity, from 1992 to 2012. What have you learned so far?

DD: The first major finding is that we’ve learned that neuro scientific evidence is widely used throughout the criminal justice system. The second kind of finding is this evidence is mostly used by defense attorneys, and most of these cases are death penalty cases. I think they’re death penalty cases because the stakes are so high. People don’t plead guilty as much. They go to trial. The trials last a long time. There’s a lot of money spent. Many of these people in these death penalty cases are brain damaged, or have all sorts of problems.

The arguments are made to mitigate a case down from death to someone … something where somebody wouldn’t be executed, but it’s also used for all sorts of defenses, including insanity, diminished capacity, et cetera. The third major finding is that a disproportionate number of lawyers who don’t use neuro scientific evidence are found to be incompetent because of that. In other words, courts expect attorneys today to use neuro scientific evidence, to introduce it into court when it’s relevant, and to do it correctly.

PV: We’ve reached a point basically where it’s not only is it being used, but it’s if you don’t use it, it’s considered improper.

DD: That’s right. If you don’t use it, it’s considered improper. I wanted to emphasize that it’s very hard to find somebody incompetent. Probably less than 1% of all attorneys are ever get that kind of disqualification. In my data set, I’ve found situations where up to 20% of attorneys are found to be incompetent for not introducing this evidence. That’s a really extraordinary result.

PV: Any sense of how successful this is used in defense cases?

DD: It’s hard to determine how successful it is because there’s so many things going on in these cases. That said, because attorneys fight so much to get this evidence into court, I think they believe that it certainly has a strong chance of being successful. I’ve certainly seen a lot of cases where it seems to be very influential on judges.

PV: You talk a lot about using it in defense cases when it comes to the death penalty. Can you talk a little bit about when it’s used by the prosecutor?

DD: So I included in my database cases in which victims had brain injuries. I have cases in which defendants have brain injuries, and the arguments are used by defense attorneys; but there are about a third of my sample are cases in which victims have some kind of brain injury because they’ve been injured by a defendant. That’s introduced into court to suggest that the defendant intended to do what they did, or to suggest that the defendant is a very violent and dangerous person.

A lot of the cases in which victim neuro scientific evidence is analyzed is almost always cases involving children, and a lot of those cases are shaken baby cases. In these cases, prosecutors have been immensely successful until relatively recently using that kind of argument.

PV: In my introduction, I talked about the film, Minority Report, and this whole idea in this fantastical future setting about being able to predict how people will act, whether or not they will commit crimes. I feel like this is the area where that would really come into play. It sounds like there have been instances, especially when it comes to using it as a defense, where this might become an issue. Can you talk a little bit about that? You mentioned Hinckley in particular.

DD: Yeah, Hinckley in particular, because Hinckley was … a CAT scan was used to suggest that he had a certain kind of brain damage that may have rendered him particularly impulsive or susceptible to acting out in the way that he did, or make him more violent. Some of the new technology that people hear about, they’re used in court yet. So for example, people at Harvard who can measure or distinguish between true and false memories in a brain. The way they do that is they test subjects with lists of words. You have to memorize 20 words, and you think ‘candy’ was in the list, but when you’re repeating back, you say ‘chocolate’ instead. That’s going to be a false memory, and they can tell the difference between a true and a false memory.

That said, those people wouldn’t testify in court. They don’t think their science is ready. It’s one to thing to say someone’s brain damaged, and their brain damage looks like some … is on the level of a schizophrenic, or … it’s a type of brain damage that would suggest this person is very impulsive. It’s an entirely different thing to say they’re talking about a false memory based on our scan of them, or … our technique, the P300 response indicates they were actually at the scene of the crime. That’s something that would overwhelm a jury so much. It would have so much weight. It could be considered, at least in legal terms, more prejudicial than probative.

PV: I want to go back to the part where you talked a little bit about neuroscience being used in defense cases, and specifically how there’s sort of an ethical quandary involved in using it as a defense. If you are a defense lawyer, and you claim that your client did X, Y, Z, because something was going on in their brain that wasn’t working right, … I’m being colloquial, obviously, here.

DD: Right, right.

PV: That opens you up to the possibility that if they’re that damaged, that they might not be able to be released back into society.

DD: Well, that’s right. I mean this is a concern that you see in court cases. It’s one of the biggest explanations that attorneys have for not introducing this evidence. In other words, they’re saying it was a defense strategy not to introduce evidence of brain damage because I was concerned that the jury might react very negatively, and think this person is going to be a future danger, and just hurt again. It is an ethical consideration.

That said, at least my research or my analysis of the cases I have would suggest if you’re going to err, you should probably err on the side of admitting it to a jury because it seems to have quite a mitigating impact. We have seen evidence of that in particular cases, where juries are questioned. They’ll say that they thought it was a valid explanation for why somebody did what they did.

PV: Yeah. Have there been a lot of cases where juries have said, ‘Okay, well we buy that defense that your brain damage caused you to commit this crime, but at the same time, this is proof that you’re too dangerous to be let go.’

DD: I have found cases, and I have cases in my data set where prosecution, at least, is arguing that the defendant is going to be a future danger. It’s this double edge sword issue that comes up. The defense attorney introduces the evidence, and the prosecution uses that evidence to suggest that the defendant is going to be a future danger. Whether that affects juries, it’s really hard to tell cause and effect, because again, this happens so much in cases where there’s a lot of violence; and maybe that’s what’s overwhelming the jury.

That said, I did want to emphasize that in a lot of those cases, they happen because the defense hasn’t been doing a very good job. In other words, they introduce the neuro scientific evidence. They use an expert, but that expert is the one who blurted out something to the effect, ‘This person may commit a crime again.’ In these cases, the defenses actually made a mistake, or their expert has been very sloppy. The prosecution jumps on a comment like that in an effort to use it against the defendant.

PV: Yikes.

DD: Yeah.

PV: That’s not a good defense lawyer.

DD: It’s not. I’ve seen a lot of really bad defense lawyers. There’s going to be one thread throughout all these cases is some of these attorneys are doing a really bad job. I have one case where the judge literally steps in and says, ‘This attorney is hurting their client. They’re doing their client more harm than good.’ I’ve encountered cases where defense attorneys use experts in situations where that expert has told the attorney, ‘Don’t put me on the stand. I’m going to hurt your client inadvertently.’ The attorney puts them on the stand anyway.

When we’re talking about future dangerousness, it has to be put into a situation where people can understand why that person appears to be a future danger. It’s not because that jurors necessarily react so negatively to this evidence. It’s because it’s been so poorly introduced into court that it’s sort of a gift for the prosecutor to make a future dangerousness argument.

PV: So we basically, all of this needs to be taken with a giant grain of salt, it sounds like.

DD: A giant grain of salt, and with a reminder that attorneys really have to do their homework if they’re going to be working with this evidence, and arguing on behalf of defendants. I think one thing to emphasize is maybe the ‘Minority Report’ scenario is … There’s some sense of reality to that. I see us getting to that. We can already … scientists are already starting to try to measure what’s going on in people’s heads, in terms of whether somebody intends to do something. The science is there already. It’s not … sufficiently sophisticated or refined to introduce into the courtroom, but we know some day it will be.

With every passing year, this neuro scientific evidence gets more precise. A number of people in this area have said that within 10 years, it may be already at the level precision of DNA evidence, where if somebody has a certain kind of brain damage, we’ll know much better or have a much better explanation of what that involves.

PV: One thing I’ve heard is that there’s a kind of growing understanding of how in early life, when you’re a child, that if you are exposed to an unhealthy environment, if you are not given good nutrition, and you’re surrounded by violence, that, that can have an effect on your brain development in ways that will never change back.

DD: Absolutely. I think a key message to take away from this, the introduction of neuro scientific evidence into the courtroom, is this evidence helps us most in trying to assess the effects of the environment on somebody’s behavior, more than anything internal going on, necessarily. In other words, I think a big concern with neuroscience is it’s going to make people look very different from one another in terms of their brain capacity. When in fact, what I think it really does is show us how powerful a bad environment can be, and what we should do, and that we as a society could do a much better job in cleaning it up.

PV: Yeah, so … I mean we’ll never get past … I mean obviously there’s going to be people who are saying, ‘Well, some people are just beyond hope. They’re just naturally evil.’ Other people will say, ‘Well, maybe that’s true, but let’s also take a look at where they came from, and who they were surrounded by, and how they came to that point.’

DD: Absolutely. I really don’t like the word ‘evil.’ I think it-

PV: That’s not a court term, is it?

DD: Well, except I’ve heard an awful lot of judges use it. Yeah, so …

PV: Not a technical term.

DD: It’s not a technical term. When I’ve heard a number of judges use it, and I always say look, this is really much more of a … actually, it’s much more of a religious term, isn’t it? Or, something along those lines, but it’s certainly widely used, and something that would be used by a juror. I think with the introduction of neuro scientific evidence and the more we learn about human behavior, maybe we as a society, or we as jurors would be less likely to use a term like someone was evil, as opposed to someone has substantial amount of brain damage, and they were widely influenced by their environment.


Patrick Verel can be reached at or (212) 636-7790.