In November 1988, Christopher Ochoa was interrogated by police about the brutal rape and murder of Nancy DePriest at a Pizza Hut in Austin, Texas. He was questioned for nearly twelve hours. The cops told him that his best friend, Richard Danziger, had already linked him to the crime scene. They said that Ochoa would be given the death penalty - and showed him where on his arm the needle would go - unless he confessed and pled guilty.

And so that’s what Ochoa did. He testified that he and Danziger had planned to rob the Pizza Hut, and then tied up the victim with her bra before raping her; they only shot the victim in the head after she recognized them. (Ochoa and his friend worked at another Pizza Hut in the area.) During the trial, Ochoa testified against Danziger – who had maintained his innocence – and both men were sentenced to life in prison.

In 1996, a convict named Achim Josef Marino serving three life sentences wrote letters to various Texas officials insisting that he had raped and killed DePriest, and that Ochoa and Danziger were both innocent. Marino said that evidence linking him to the crime scene, including the keys of the victim, could be found at his parents’ home. After recovering this evidence, Austin police then re-interviewed Ochoa. His story, however, remained the same: he had committed the crime. He was a guilty man.

In fact, it would take another three years before students at the Innocence Project at the University of Wisconsin Law School in Madison were able to test semen recovered from the crime scene. The genetic tests proved that neither Ochoa nor Danziger had any involvement with DePriest’s rape and murder. On February 6, 2002, both men were exonerated.

There is no more potent form of legal evidence than a confession. To know that someone confessed is to assume they must have done it: why else would they submit a guilty plea? And yet, the tragic files of the Innocence Project demonstrate that about 25 percent of false convictions are caused by false confessions, as many people take responsibility for violent crimes they didn’t commit.

These false confessions have multiple causes. Most often, they seem to be associated with devious interrogation techniques (telling Ochoa that Danziger was about to implicate him) and the use of violence and intimidation during the interrogation process (insisting that Ochoa would be sentenced to death unless he pled guilty.)

And yet, false confessions are not simply a matter of police officers scaring suspects into admissions of guilt. In many instances, they also involve the generation of false memories, as suspects come to believe - typically after hours of intense and repetitive interrogation – that they committed the crimes in question. In the scientific literature, these are sometimes referred to as “honest lies,” or “phantom recollective experiences.”

What’s so unsettling is how easy it is to implant false memories in someone else’s head. This ease is old news: in the mid-1990s, Elizabeth Loftus and colleagues famously showed how a few suggestive interviews could convince people they’d been lost in a shopping mall at the age of six. Subsequent studies have extended her findings, persuading subjects that they’d been rescued by a lifeguard after nearly drowning or had tea with Prince Charles. You can trick people into misremembering details from a car accident and get them to insist that they shook hands with Bugs Bunny at Disneyland.

However, a new study by the psychologists Julia Shaw and Stephen Porter takes this false memory paradigm in a most disturbing direction, revealing a clear connection between false memories in the lab and false confessions in the legal system. In their paper, Shaw and Porter demonstrate that a majority of people can also be persuaded that they committed serious crimes. Their memories were rich, detailed and convincing. They were also complete fictions.

Shaw and Porter began the study by contacting the primary caregivers of 126 undergraduates, asking them to report “in some detail on at least one highly emotional event” experienced by the student during childhood. Then, sixty of these students were questioned three times for about forty minutes, with each of the interviews occurring a week apart. The interviews followed a technique proven to elicit false memories, as the scientists described two events from the subject’s childhood. The first event was true, at least as described by the caregiver. The second was not.

The novelty of this study involved the nature of the false event. Half of the subjects were randomly assigned to a “criminal condition,” told that they had committed a crime resulting in police contact. The crimes themselves varied, with a third told they had committed assault, another third that they had committed assault with a weapon, and the final third that they had committed theft. Those in the non-criminal condition, meanwhile, were assigned one of the following false memories: they’d been attacked by a dog, injured during a powerful emotional experience, or lost a large sum of money and gotten into a lot of trouble with their parents.

During the interview process, the subjects were asked to recall both the true and false events. Not surprisingly, the subjects had trouble recalling the fictional event they’d never experienced. The scientists encouraged them to try anyway. To make the false memories feel more believable, they embedded their questions about the event with accurate details, such as the city the subject had lived in at the time, or the name of a friend from his or her childhood. They also relied on a collection of interrogation strategies that have been consistently associated with the generation of false confessions. Here are the scientists describing their devious method:

"The tactics that were scripted into all three interviews included incontrovertible false evidence (“In the questionnaire, your parents/ caregivers said. . .”), social pressure (“Most people are able to retrieve lost memories if they try hard enough”), and suggestive retrieval techniques (including the scripted guided imagery). Other tactics that were consistently applied included building rapport with participants (e.g., asking “How has your semester been?” when they entered the lab), using facilitators (e.g., “Good,” nodding, smiling), using pauses and silence to allow participants to respond (longer pauses seemed to often result in participants providing additional details to cut the silence), and using the open-ended prompt “what else?” when probing for additional memory details."

In the two follow-up interviews, the subjects were, once again, asked to describe their false memories. In addition, they were asked a number of questions about the nature of these memories, such as how vivid they seemed, and whether or not they felt true.

The results were shocking. Of the thirty people assigned to the criminal condition, twenty-one of them (70 percent) now reported a false memory of being involved in a serious felony that resulted in police contact. What’s more, these “honest lies” were saturated with particulars, as the subjects reported an average of more than 71 details from the non-existent event, including 12 details about their interactions with the police officers. “This study provides evidence that people can come to visualize and recall detailed false memories of engaging in criminal behavior,” write Shaw and Porter. “Not only could the young adults in our sample be led to generate such memories, but their rate of false recollection was high, and the memories themselves were richly detailed.” While the subjects’ true memories were slightly more detailed than their false memories, and they were a bit more confident that the true events had happened, there were no obvious distinctions in form or content between their real and imagined recollections.

The study, then, is yet another reminder that our memory takes a post-modern approach to the truth, recklessly blurring together the genres of autobiography and fiction. Although our recollections tend to feel accurate and immutable, the reality is that they are undergoing constant revision: we rewrite our stories of the past in light of the present. (This is known as reconsolidation theory.) The end result is that the act of remembering is inseparable from misremembering; the memoirs we carry around in our heads are overstuffed with bullshit.

What’s most disturbing, of course, is that we believe most of it anyway, which is why Shaw and Porter were able to make people remember crimes they’d never committed. When the experiment was over, after three weeks of interviews, the scientists told the subjects the truth: There was no assault, no weapon, no theft. They had been innocent all along.

It took nearly fourteen years for Christopher Ochoa to be told the same thing.

Shaw, Julia and Stephen Porter. "Constructing Rich False Memories of Committing Crime," Psychological Science. 2015.