In short
Episode topic: The 1991 Herbert Weinstein case and how PET brain scans entered U.S. courts, plus neuroscience’s limits in determining criminal responsibility.
Guests/backgrounds
Josh May, ethics professor at the University of Alabama at Birmingham; Anthony Wagner, neuroscientist at Stanford; Adina Roskies, philosopher of neuroscience/neuroethics.
Key claims
Weinstein’s PET scan showed an arachnoid cyst pressing on his frontal lobe with reduced glucose metabolism, which defense argued could impair executive control and reduce responsibility (“brain defense”). Courts must decide admissibility via standards like Frye/Daubert, but science often yields population-level correlations that don’t cleanly prove individual intent. Brain-based lie detection (fMRI + AI) is promising but not precise enough for courtroom use soon.
Notable examples
People v. Weinstein (first judge to admit PET evidence); later Roper v. Simmons (juvenile death penalty overturned using brain-imaging research).
Written by AI. May contain mistakes. Listen to the episode to check what was said.
Chapters
Tap a time to open that second in VOA Car Accident Experience
0:03 to 1:16
The host shares a personal experience of quickly filing a claim with GEICO.
“It's the only business software you'll ever need.”
Neuroscience in the Courtroom
4:47 to 10:30
Exploration of how a PET scan of Weinstein's brain was used in his trial and its implications for legal responsibility.
“He had a orange-sized cyst pressing on his frontal lobe.”
The Brain Defense Argument
10:30 to 15:17
Discussion on the brain defense strategy and its potential impact on jury decisions in criminal cases.
“that the scan showed that the cyst could reasonably have impacted how he behaved.”
The Impact of Neuroimaging in Court
17:31 to 23:27
Explore how neuroimaging has affected legal decisions and the challenges it presents.
“The decision to admit the PET scan in Weinstein's trial in 1992 had enormous implications.”
Advancements in Brain Science
23:28 to 26:56
Understand the evolution of brain imaging techniques and their implications.
“So we have these moments of sort of what seem like bursts of discovery, often tied to changes in what we can do as scientists, the techniques we have.”
Philosophical Questions on Agency
26:57 to 28:00
Delve into the debates surrounding consciousness and human agency.
“The answer to that big question is best left to neuroscience.”
Setting the Scene
28:00 to 28:22
Learn about the protagonist's journey as they board the train to Manhattan.
“So she got on the first A train and headed towards Manhattan.”
Setting the Scene
28:25 to 28:53
Learn about the protagonist's journey as they board the train to Manhattan.
“You'll get access to all of Vox's journalism.”
Transcript
Automatic transcript. May contain errors.0:00Anthony Wagner:Support for this show comes from Odoo. Running a business is hard enough, so why make it harder with a dozen different apps that don't talk to each other? Introducing Odoo. It's the only business software you'll ever need. It's an all-in-one, fully integrated platform that makes your work easier. CRM, accounting, inventory, e-commerce, and more. And the best part? Odoo replaces multiple expensive platforms for a fraction of the cost. That's why over thousands of businesses have made the switch. So why not you? Try Odoo for free at odoo.com. That's O-D-O-O dot com.
0:40Josh May:When I scraped my car in that parking garage, I was worried that it could be a long process to take care of it. Like a landscaper's first day trimming a hedgeman.
0:48Anthony Wagner:I have definitely already been here. Now, was it left, right, or right, left? Well, maybe I'll cut a path out and find my way back later.
1:00Josh May:But it wasn't like that. I filed a claim in under two minutes on the GEICO app, and they handled it from there. It was taken care of almost as quickly as it happened.
1:07Anthony Wagner:It feels good to get help quick. It feels good to GEICO.
1:16Josh May:The year was 1991, and Herbert Weinstein was a retired ad executive.
1:22Anthony Wagner:He's 65 years old, and he's living in Manhattan, a 12-story apartment.
1:27Josh May:I called up Josh May to tell me this story. He's an ethics professor at the University of Alabama at Birmingham.
1:34Anthony Wagner:Gets into an argument with his wife at the time, and he apparently got into such a fit that he strangled her and then tried to make it look like a suicide by pushing her body out of the 12-story window.
1:50Josh May:There was a 911 call. The officers responded to claims that a woman may have jumped. When the police arrived, they saw a woman lying on the sidewalk in broad daylight. And they saw a window open in the building above. Weinstein was in the lobby. One of the officers asked the man if he lived there. He did, he replied, and gave them his name. He said he lived upstairs with his wife, Barbara. He didn't know where she was. Then Weinstein and the officers went up to the 12th floor. He got agitated once they reached the apartment. Where was she? Why were there officers there? The officer told him that there was a woman dead on the sidewalk.
2:35Josh May:And Weinstein's like, is it Barbara?
2:37Anthony Wagner:He was acting kind of strangely. Apparently he seemed a bit unconcerned that his wife had just died and that he was being a suspect in this case.
2:48Josh May:The officers asked him questions. Why do you have a scratch on your face? And they noticed that one of his hands was black and blue, with a spot of blood on it. And so then he came clean.
2:59Anthony Wagner:There were witnesses or people who saw that he had pushed the body out, and he pretty readily confessed to it.
3:06Josh May:To everything. He confessed to strangulation, he confessed to throwing her out the window in a panic, and he admitted to covering up the crime. And so the officers arrested him.
3:20Josh May:Weinstein's defense attorney was struck by how relaxed his client seemed in the days after the crime. And so he ordered a psychiatric evaluation. The man's history indicated nothing glaring. He had no criminal record, no history of violence, and there was no known motive. His defense team did a PET scan, basically a snapshot of his brain. What they found was shocking. And in the ensuing trial, People v. Weinstein, it was the first time a judge allowed a PET scan as evidence to determine the defendant's guilt or innocence. What I find so fascinating, though, is that this PET scan sort of opened up a Pandora's box in the courts.
4:09Josh May:As one New York Times writer put it, this case was arguably the moment that neuroscience began to transform the American legal system.
4:22Josh May:Today, what is the role of neuroscience in the law? And what are its limits? I'm Amy Padula, and this is Unexplainable.
4:46Josh May:So, when Weinstein's PET scan came back, the image revealed something alarming. A big, dark circle.
4:55Anthony Wagner:He had a orange-sized cyst pressing on his frontal lobe.
5:01Josh May:It was an arachnoid cyst, which forms in the arachnoid tissue of the brain. There are sort of multiple layers of protective tissue that surround the brain. The PET scan showed diminished glucose metabolism near the cyst.
5:15Adina Roskies:The arachnoid, sort of the middle layer, predominantly has cerebral spinal fluid in it. These tissues essentially provide some protection to the brain.
5:24Josh May:Anthony Wagner is a neuroscientist at Stanford University. So the cyst was on the left side of Weinstein's brain.
5:33Adina Roskies:Essentially, it's sort of a filling up. It's a little sack within the arachnoid space. It's the filling up of that space with cerebral spinal fluid. And so it begins to fill up. it could actually sort of impinge on the underlying brain tissue. In a small percentage of cases, it could impact brain function. Most individuals who have arachnoid cysts, there are no consequences for behavior, for neural function, but a small percentage it can. And so it's this sort of impinging on the brain that can perhaps change brain function for some individuals.
6:06Josh May:Weinstein's cyst was also, critically, pressing up against his frontal lobe.
6:12Adina Roskies:At a high level, we know a lot about the frontal lobes, the frontal lobes' roles in allowing us to sort of represent our goals, our plans, to represent the context that we're in and to try to bring our behavior in line, act appropriately within a particular context.
6:28Josh May:So, Anthony says, for instance, if you had a wound in this area of the brain, your behavior might change. Say you're in your doctor's office. Maybe the phone rings. Someone with damage in that part of the brain might simply just pick up the phone.
6:46Adina Roskies:That's a habitual response. These are things we do with phones. But given the context in which one is in, it's not your home, it's not your office, it's your doctor's office, most of us would not sort of go ahead and pick up the phone, right? So, lateral, dorsolateral prefrontal cortex or lateral prefrontal cortex interacting with other brain regions allow us to represent our goals, our context, bring our behavior in line with and to produce contextually appropriate behavior. One might be a bit more impulsive. On average, individuals who have prefrontal lesions or impairment in prefrontal function might be a bit more impulsive.
7:18Adina Roskies:They might struggle to regulate emotion. They might struggle to regulate overlearned or habitual behaviors that are not context relevant.
7:30Josh May:So, Weinstein's defense team has this scan at their disposal. The prosecution was really anxious about it. Because even though Weinstein had already admitted to what he had done, was he going to get off easy because of the cyst? Because maybe Weinstein was one of the unlucky ones that did have cognitive impairment. But it's tricky. The PET image was taken after the crime was committed, not the day of the crime. The scan proved he had a cyst in his brain. But that's about all it showed.
8:03Adina Roskies:One of the challenges for the courts is to try to figure out what evidence should they allow in. Either the prosecution or the defense, one side wants to bring the evidence forward. And do you just have a free-for-all? Or is there some process upon which or by which the court should be making these decisions?
8:22Josh May:We actually have a special process in the court system to help us figure out what scientific evidence is admitted and not admitted. One is something called the Fry Standard. Today, we have another one called Doebert.
8:33Adina Roskies:The Frye standard at the highest level is to have experts or have one or both sides of the case weigh in on whether or not this new scientific method is generally accepted as doing the thing that it's being proffered to do in that particular case, sort of setting up the judge as essentially the gatekeeper. Should I let this particular scientific evidence enter the courtroom, be presented to the jury? Does it meet this set of criteria? What do we know about that? And so in Frey hearings and Dabber hearings, these are pretrial hearings where there's presentation from both sides about the state of the science.
9:16Josh May:In the Weinstein case, the judge conducted a special hearing for the scan, and the Frey standard was applied. If he found that the PET scan was a generally accepted technological tool, then experts could testify about whether that scan supported a claim of brain dysfunction. They could argue that because of this cyst and its location near the frontal lobe, Weinstein lacked the capacity to behave normally. That he had gone temporarily insane. But this hearing would also give the prosecution the opportunity to ask questions and bring in experts to argue like, well, just because Weinstein's frontal lobe was affected, it doesn't mean it could cause violent behavior.
10:01Josh May:And it doesn't follow that it caused him to commit this crime. Biology says one thing. There was a cyst on this man's brain. We know that from the PET scan. But Josh May says, in the law, the law is interested in something else.
10:17Anthony Wagner:Really, in the law, it's not largely about the science. It's about, you know, can you convince a jury?
10:24Josh May:Okay, so the judge poured over the testimonies of physicians and scientists who had defended both arguments, that the scan showed that the cyst could reasonably have impacted how he behaved. Other experts testified that the mere existence of the cyst was not the cause of this man's actions. So Weinstein's lawyer suggests that his client should not be held responsible for his actions because of this, because of the presence of this. That's essentially the argument.
10:50Anthony Wagner:Yep, that he's not fully in control. At the very least, he should be held less responsible. The question here is about whether he really had control over it. And so that could be a mitigating factor.
11:01Josh May:This is really what we call the brain defense. Basically, my brain made me do it. Was Weinstein in control of what he did? Or was his brain impacted by this cyst in this specific area of the brain that we know controls executive function, personality, and some behavior? Because of that, did he make a sudden, awful choice?
11:28Anthony Wagner:The district attorney got worried that a jury would possibly acquit if they saw this large cyst pressing on his frontal lobe.
Read the full transcript
11:37Josh May:Basically, oh, so there's a cyst on his brain. They might assume his brain made him do it and then let him off.
11:43Anthony Wagner:The prosecution, I think it's mostly that they're worried that even if it's a bad argument, that a jury might be swayed by it. And especially in Weinstein's case, the brain imaging is very powerful, compelling evidence that there is that brain abnormality. And it is so tempting to go from brain abnormality to absolving of guilt in the minds of some people, at least.
12:08Josh May:It's a hard argument for the prosecution. They want to argue that this man was not insane and that he committed this crime, that he admitted to it. Sister not, he did this.
12:19Anthony Wagner:So I think that the prosecution is hedging their bets there. And they're worried that some people might make that inference, even if it's not a very good one. I think that's exactly what the district attorney was worried about, is that this could be convincing or compelling to a jury. And it is, right? If you can have some what feels like very solid, hard evidence through some actual physical object pressing on his brain, that can be pretty compelling to some juries.
12:50Josh May:In October of 1992, the judge decided that Weinstein's scan could be admitted as evidence. But they couldn't explicitly say that the cyst caused him to be violent. Tensions rose. The prosecution worried that this was the end of their case. The PET scan was so promising, it could sway the jury. And then, on the morning of jury selection, the prosecution team made a deal. They would let Weinstein plead guilty for a less significant sentence.
13:23Anthony Wagner:Arguably, brain imaging really reduced someone's sentence. Where you had a charge of second-degree murder down to manslaughter.
13:36Josh May:Weinstein was sentenced to 7 to 21 years in prison. He also never got the cyst removed. It was too risky. But the thing that strikes me the most, the entire time he was there, more than 12 years, he showed no signs of violence.
13:59Josh May:After the break, how neuroimaging changed and entered the courts after Weinstein. And what's next?
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17:27Josh May:Rain! Rain! Rain! Rain! Rain! The decision to admit the PET scan in Weinstein's trial in 1992 had enormous implications. It arguably pushed neuroimaging into the courtroom for good. In 2005, a super high-profile Supreme Court case called Roper v. Simmons overturned the juvenile death penalty, an argument that was made citing neuroimaging research showing differences between teenage and adult brains.
18:01Neuroimaging has this much of an impact on the court system, a system that operates completely differently than science.
18:09Josh May:And yet, both fields are sort of bound up in each other, knotted like cat's cradle.
18:16Adina Roskies:You know, scientists, we have high thresholds for wanting to draw an inference and believe that we've discovered something and are comfortable sort of reporting it out to the broader scientific community. We want there to be fairly convincing evidence that it's more likely than not due to chance that we see something. We still have the luxury that when we do our experiments, we should have, and we typically set our standards exceptionally high, and we want to have compelling evidence before we're going to draw an inference. So we can wait out. We can do additional experiments. We can gather more evidence before we actually make a decision, make a determination, write a paper and say, hey, I think I've discovered X.
18:57Adina Roskies:The courts have a different challenge. They have a singular case. It's sitting in front of them. They have a particular defendant. And they have to make a determination. Look, we have to make a decision. That jury or that judge has to make a determination. You can't punt it down the road. You can't do another trial five years from now and get more evidence. The jury has to make some determination. The basis upon their decision about guilty, not guilty, the ability to sort of form intent, the ability to engage in more reasoned, goal-directed, sort of thoughtful sort of behavior, that seems like it's often a key question in these trials.
19:45Josh May:I keep thinking about something Adina Roskies told me. She's a philosopher of neuroscience who specializes in cognitive neuroimaging and neuroethics. She says scientists are interested in understanding how things work and what we know and don't know at a moment in time. But that is a very different project than holding someone responsible for their actions.
20:07Anthony Wagner:We often have to average across multiple trials, often across multiple people, in order to get any kind of general statement about how brains do the kinds of things that they do. And what we reach is some kind of biological mechanistic understanding. Actually, the level of neuroimaging, we rarely get to the level of mechanism. What the kinds of results of the science give you tend to be general statements about populations when you're talking about neuroimaging. The law is typically concerned with social structure and individual acts, and it's really hard to take the kind of science that's predicated on populations and generalities and apply it to these individual acts.
21:05Anthony Wagner:And the law works with a very different framework than the sciences work with. I mean, it's very unclear how to apply knowledge in one domain to another domain. I don't think there are any clear deductions.
21:24Josh May:If the evidence is imperfect, if an image of a brain only suggests something about that brain without being definitive about it, Should this kind of evidence have been admitted in a case like Weinstein's after all?
21:40Anthony Wagner:I do think that we have to compare it to other kinds of evidence that we already allow into courts. And really, science has revealed that a lot of the evidence we admit is not very reliable. Things like eyewitness testimony is not very reliable, we know. And yet, we don't banish it from courts. And I think part of that reason is that we often don't have a lot of evidence when it comes to these very high-stakes decisions. and we're trying to figure out, you know, whether somebody has committed murder or at least a certain degree of murder and it would be helpful if we had more evidence rather than less.
22:13Anthony Wagner:So I'm a bit concerned about pulling evidence off of the table and presuming that juries aren't capable of trying to assess that evidence. It's a hard issue to resolve but I think it's better in general to give them more evidence rather than less.
22:32Josh May:A more fine-tuned technology emerged after PET called fMRI, functional magnetic resonance imaging.
22:40Adina Roskies:FMRI is really the workhorse now of modern sort of human systems neuroscience. It's transformed our field in so many different ways. FMRI today is the dominant technique used to try to understand brain function.
22:54Josh May:FMRI looks at changes in oxygenated blood flow in the brain that show changes in brain activity. Anthony Wagner says after FMRI broke through in the 90s, there have been these bursts of development with the technology. And another phase has been underway for a while.
23:14Adina Roskies:The combining of current modern day AI tools and systems with behavioral phenotypes of people, behavioral, rich behavioral assaying of people, but also underlying neural signals. And I think that that's going to give rise to an explosion in the field of neuroscience as well as obviously in many other fields. So we have these moments of sort of what seem like bursts of discovery, often tied to changes in what we can do as scientists, the techniques we have. But on the whole, science is slow. It's incremental. It's accumulating evidence over years.
23:51Josh May:He says we can now get closer and closer to understanding the brain at increasing levels of specificity. Right now, fMRI has been used in combination with machine learning tools.
24:04Adina Roskies:Classifiers that can be trained over brain patterns to detect mental states like, is the person remembering the face that they're being presented at this moment, versus perceiving the face as novel? Are they perhaps lying versus not lying?
24:20Josh May:Lying. There's been a tremendous push from the mid-2000s onward to develop a reliable brain-based lie detector. Anthony was actually part of a huge effort through the MacArthur Foundation to assess the literature on the validity of brain-based lie detection.
24:37Adina Roskies:The details of what's in somebody's mind are still fairly limited. I think it's not clear how far we'll get, but I'm pretty confident that leveraging brain patterns as inputs to AI models will allow us to do, and we're already beginning to see this on the visual perceptual reconstruction, we will do even better in terms of being able to, it's a little scary, this notion of mind reading, trying to understand and reconstruct. And I think that those discoveries will continue to come, and there'll be many others. It's pretty clear to me that there's not consensus within the neuroscience community that fMRI can be used to differentiate with a known precision, differentiate between truth and lying.
25:22Adina Roskies:It's really hard science to do. I think of myself as a memory scientist. Some of the problems we work on, they're easier problems because Because in a lab setting, you really cannot create lies of real-world experiences with real stakes that are going to elicit the kind of potential threat.
25:43Josh May:It's very hard to concoct a lie in a lab.
25:47Adina Roskies:When you're lying, if you're caught lying, you cannot create experimental settings that are analogs of what might be happening in the real world. The short answer to the question, is it too early? The answer is yes, it's too early. from my perspective, which is we just don't know.
26:05Josh May:So brain-based lie detection is unlikely to get anywhere near something, like the Fry standard, any day soon. But it could. I keep thinking about something Josh May asked. Are we really just these physical things, controlled by our brains? And do we actually have any agency over our actions?
26:26Anthony Wagner:That's still heavily debated. You might think that we have made some progress, but even neuroscientists will tell you, especially when it comes to consciousness, our experiences, we really just have no idea how that arises in the brain. And there are these deep questions about whether that is a fundamentally different thing, our private experiences versus this brain activity. Could they just be one and the same thing, or are they just fundamentally different? And that's still a hotly debated issue in philosophy, but also in neuroscience. There are these longstanding philosophical questions about, does that mean that we are just our brains?
27:01The answer to that big question is best left to neuroscience.
27:07Josh May:And as science evolves, our understanding of justice could too.
27:19Josh May:If you want to read more about the Weinstein case, you can read a great book by journalist Kevin Davis called The Brain Defense.
27:30Josh May:This episode was produced by me, Amy Padula. It was edited by Joanna Solitaroff, mixing and sound design from Joe Plourd, and music from Noam Hassenfeld. Melissa Hirsch checked the facts. Julia Longoria and Jorge Just are our editorial directors. Sally Helm is the fact that brain information travels at speeds up to 268 miles per hour. And Bird Pinkerton headed for the subway. And as soon as she walked down the stairs, she looked at the walls. White tiles in a station. She must be close. So she got on the first A train and headed towards Manhattan. As always, thank you to Brian Resnick for co-creating the show with Noam and Bird.
28:16Josh May:If you'd like to support the show and the journalism that Vox does, we would love it if you would become a member. It's very easy to do. Just go to vox.com slash members. You'll get access to all of Vox's journalism. For those of you who have emailed us to let us know that you signed up because of Unexplainable, thank you. If you can't join our membership, that's okay. If you wanted to leave us a nice review on your podcast platform, five stars, or a written review, we would really, really appreciate it. Or you can tell someone in your life that they might want to listen to the show. Those things make a real difference.
28:49Josh May:Unexplainable is part of the Vox Media Podcast Network. We will be back soon with another episode about everything we don't yet know.
29:05Thank you.
From the publisher
A man committed a crime. He admitted it. Then something alarming showed up on an image of his brain. The criminal case that followed in 1991 brought neuroscience into the courtroom for good. How does our ever-changing understanding of the brain impact how we approach justice?
Guests: Josh May, professor of philosophy, University of Alabama, Birmingham, author of Neuroethics: Agency in the Age of Brain Science, Anthony Wagner, neuroscientist and professor of psychology, Stanford University Memory Lab, and Adina Roskies, professor of philosophy, UC Santa Barbara.
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