Is Scott Peterson Innocent?
Part one: human lie detection and demeanor evidence.
Posted Jan 18, 2018
Back in 2004, when Scott Peterson’s trial was the courtroom media circus du jour, I was completely convinced—like just about everyone else—that Scott Peterson was stone cold guilty of murdering his pregnant wife Laci and their unborn son Connor. I mean, as high-profile murder trials go, this one seemed even easier to crack than O.J. But A&E's new docuseries The Murder of Laci Peterson, which is based on newly discovered evidence revealed in recent court filings, makes you seriously question that assumption.
Even accounting for whether or not the show’s creators had an agenda to make Peterson look innocent, the new evidence—the actual evidence—now being considered by a federal court in California should cause any open-minded person to question the evidence that originally convicted him. And I’m not just reacting to the provocative reexamination of evidence presented in the docuseries, I also read the court filings.
The new evidence makes a persuasive case that numerous witnesses saw Laci alive and walking the family dog—after Scott Peterson had left home for the day to stop at work and then fish in the San Francisco Bay (which, if true, totally undermines the state’s case against him). The evidence also suggests that Laci, upon returning from her walk, confronted shady characters burglarizing the house across the street from the Peterson’s home and that this incident started a chain of events that most likely led to her murder. And that’s just the tip of the iceberg.
But regardless of whether or not the docuseries convinces you that Peterson is innocent, it presents a fascinating case study of the human frailties—the psychological flaws—that often cause criminal investigations to go awry. I recently wrote about these psychological traps in my new book Blind Injustice: A Former Prosecutor Exposes the Psychology and Politics of Wrongful Convictions. In the book, I focus on my own cases from my years as a prosecutor, and then more recently as an innocence lawyer with the Ohio Innocence Project (which has now freed 25 innocent people who served 471 years in prison for crimes they didn’t commit). In the book, I also apply principles of psychology to the police investigation depicted in the Netflix docuseries Making a Murderer. I wish The Murder of Laci Peterson had been released when I was still writing Blind Injustice, because it really highlights some of these psychological issues better than any other TV show or movie in recent memory.
First, Scott Peterson was convicted primarily because of what we call “demeanor evidence.” Peterson undeniably appeared “aloof” and “unemotional” if not cocky when caught on camera by the paparazzi during the investigation and then at his trial. This caused America’s most famous prosecutor-journalist, Nancy Grace, to preach on an almost nightly basis that Peterson was “lying” and “hiding something” and therefore guilty. And the jurors said after the trial that Peterson’s remorseless demeanor was perhaps the most critical factor that caused them to convict him and send him to death row.
In recent years, the innocence movement has exposed more than 2,000 wrongful convictions in America, with the number growing at a rate of about three per week. And if we’ve learned anything from this movement, it’s that, contrary to popular belief, humans are really bad—really, really bad—at determining when someone else is telling the truth or lying. Despite what our intuition tells us, demeanor evidence just doesn’t mean that much and can’t be taken to the bank. And that’s been proven not just by the thousands of innocents who were wrongfully convicted after the police or jury disbelieved them and thought their demeanor indicated guilt, but by clinical studies as well. As I highlight in Blind Injustice, study after study shows that we are about 54 percent accurate at divining the truth from watching someone’s demeanor. Barely better than a coin flip. And cops fare no better. Things we have been told are indicative of dishonesty and guilt, such as appearing aloof or unemotional, or failing to make eye-contact, are actually not good barometers. Our collective psyches are embedded with the belief that humans are good lie detectors. But in reality, it’s just folklore—outdated pop psychology.
Indeed, there is case after case where defendants were convicted for reasons similar to Peterson—they appeared “too unemotional” or “far too aloof”—but later were conclusively proven innocent. I detail many of these cases in Blind Injustice, such as Michael Morton of Texas, who spent 25 years in prison for the murder of his wife before DNA testing conclusively proved him innocent. Not only did Morton appear unemotional, if not cocky like Peterson, but he continued sleeping in the couple’s bed where she was murdered, including the first night after she had been bludgeoned to death on that very mattress. He also did other strange things, like mowing down all of his wife’s beloved flowers the morning of her funeral. These acts seemed callous and, along with his aloof demeanor, convinced the police, the public, and his jury that he was clearly guilty. Morton’s case is eerily similar to Peterson’s, except that Peterson does not have the good fortune of DNA evidence to test years later.
And then there are the cases where everyone ganged up on the innocent person because his or her grief was so palpable that it was labeled as “over the top” and “staged.” With something as subjective as demeanor evidence, it’s damned if you do, damned if you don’t.
There are other innocent explanations for unemotional reactions as well. Some people who lose loved ones may simply not be as upset about it as one might expect. Perhaps feeling for a spouse had faded, so the sudden loss was confusing and caused an aloof, emotionless outward appearance. While insensitive, an aloof reaction in these circumstances doesn’t equate with guilt.
Everyone reacts differently to tragic situations. Fortunately, very few of us have experienced the trauma of having a loved one murdered. Some people appear aloof or emotionless because they are in shock or denial. Some people freak out. The assumption that there is an “appropriate” or “normal” way to act in an unfamiliar traumatic situation, and that those who do not respond that way are likely guilty, is simply bad psychology and bad law.
Regardless of whether or not Peterson is, in fact, innocent or guilty, it is clear that everyone—the police, the public, the media, and ultimately the jury—gave way too much weight to his demeanor. While demeanor evidence can’t be ignored, it should be used with caution and given proper weight in light of modern understandings of psychology. Otherwise, it’s the tail wagging the dog. As Peterson attorney Mark Geragos says in The Murder of Laci Peterson, “There is no playbook for grief.”
In follow-up stories, I’ll continue my discussion of The Murder of Laci Peterson with respect to the psychological phenomena of police tunnel vision (Part 2) and confirmation bias in the forensic sciences (Part 3).