The Effect of Misinformation on Memory

According to Elizabeth F. Loftus, professor of psychology and adjunct professor of law at the University of Washington, "False memories are constructed by combining actual memories with the content of suggestions received from others" (Creating False Memories)

In Creating False Memories, Loftus addresses the effect misinformation can have on memory. Her own studies, dating back to the 1970s, "show that when people who witness an event are later exposed to new and misleading information about it, their recollections often become distorted." Loftus gives two compelling examples of how misinformation can distort memory:

In one example, participants viewed a simulated automobile accident at an intersection with a stop sign. After the viewing, half the participants received a suggestion that the traffic sign was a yield sign. When asked later what traffic sign they remembered seeing at the intersection, those who had been given the suggestion tended to claim that they had seen a yield sign. Those who had not received the phony information were much more accurate in their recollection of the traffic sign.

My students and I have now conducted more than 200 experiments involving over 20,000 individuals that document how exposure to misinformation induces memory distortion. In these studies, people "recalled" a conspicuous barn in a bucolic scene that contained no buildings at all, broken glass and tape recorders that were not in the scenes they viewed, a white instead of a blue vehicle in a crime scene, and Minnie Mouse when they actually saw Mickey Mouse.

Loftus concludes: "Taken together, these studies show that misinformation can change an individual's recollection in predictable and sometimes very powerful ways."

Moreover, Loftus claims that "Misinformation has the potential for invading our memories when we talk to other people, when we are suggestively interrogated or when we read or view media coverage about some event that we may have experienced ourselves."

My question is, Did the detectives in the Modesto Police Department use misinformation to distort memories about Scott Peterson? Testimony from both Detective Brocchini and Detective Grogan suggest they did.  Additional support comes from Sharon Rocha's interview on Larry King Live, in which she "remembered" things she did not disclose at trial. 

Detective Brocchini testified that he intentionally used misinformation printed in the ModBee to plant the seeds of suspicion in several of Scott's friends. The ModBee article talked about a recent $250,000 double indemnity life insurance policy that Scott had taken out on Laci. Detective Brocchini knew this information to be false, and not only made no effort to correct it, but used it to further his own agenda.

17 Jan 2003 Detective Brocchini called Mike Richardson
At 6:40 am, Brocchini called Mike Richardson, a good friend of Scott's, and asked him if he read the ModBee. He wanted him to read an article running that day about Amber Frey and the $250K life insurance Scott took out on Laci. Brocchini suggested that Heather, Mike's wife, call Sharon Rocha for further information, and said that Scott was not welcome in any of Laci's friends' or families' homes. Later that day, Brocchini called Mike back to see if he had read the article and encouraged him to question Scott about Laci's disappearance. At the preliminary hearing, Brocchini said he had also contacted other friends of Scott's and Laci's with the intention of planting the seeds of suspicion and solicited their help to get answers to questions he was not legally allowed to ask Scott. He said he wanted them to let Scott know he was the one wanting the answers. Brocchini also talked to Aaron Fritz and Brian Argain, both of whom were friends of Laci. Defense attorney Kirk McAllister suggested in his cross examination that Aaron Fritz taped at least one of the calls Brocchini made to him, when Brocchini allegedly told Fritz that he would take Scott Peterson down.

Brocchini was very willing to use misinformation to turn Scott's friends into spies. And, Brent Rocha, in a phone call with Scott, admits that the MPD told Laci's family that they had blood evidence in the house. Armed with proof of the affair with Amber Frey, why did Brocchini and other detectives even find it necessary to use such misinformation? Is it just a routine procedure? Or did they somehow sense that the affair wasn't enough, by itself, to turn Laci's friends and family against Scott. Hence the need to embellish it with incriminating misinformation that would both add to motive and give the illusion of forensic evidence that Scott had murdered Laci.

Grogan's efforts were no less insidious. Not only was he party to giving this life insurance and blood evidence misinformation to Laci's family and friends, he also encouraged them to now "remember" what they could about Scott.

First, let's look at possible distortion of Sharon Rocha's memory. Sharon testified at trial that in Scott's first conversation with her on the night of December 24th, he told her "Laci is missing." Simple words with great potential to incriminate. However, a timeline of Sharon's statements, as provided by Grogan in his testimony during the Defense CIC, reveals that she is the first to assume Laci is missing, not Scott.

Then we have this event:

Sandy Rickard, Sharon's best friend, testified that the night before the Diane Sawyer interview, she and some other ladies were gathered with Sharon at Patty Amador's house for the purpose of trying to remember things about Scott. Patty called Grogan to tell him that she heard Laci was afraid of Scott because he was making concrete weights. Sharon made a call to Grogan to report remembering Scott had said Laci was missing when he called her on December 24. Sandy called Grogan to report that she remembered Scott coming up to her on the night of the 24th, with his hands raised, and saying that he wouldn't be surprised if they found blood in his truck.

Misinformation has the potential for invading our memories when we talk to other people, when we are suggestively interrogated or when we read or view media coverage about some event that we may have experienced ourselves.

In Creating False Memories, Loftus explores the potential problems in connection with police interrogations.

It is natural to wonder whether this research is applicable in real situations such as being interrogated by law officers or in psychotherapy. Although strong suggestion may not routinely occur in police questioning or therapy, suggestion in the form of an imagination exercise sometimes does. For instance, when trying to obtain a confession, law officers may ask a suspect to imagine having participated in a criminal act.

Loftus notes that false memories can be planted in adults who are feeling pressure to remember, such as might have been the case with Detective Grogan.

Finally, Loftus explains that "False memories are constructed by combining actual memories with the content of suggestions received from others. During the process, individuals may forget the source of the information. This is a classic example of source confusion, in which the content and the source become dissociated."


I would like to see an expert like Loftus examine the Scott Peterson investigation and conviction to determine what role misinformation had in planting false memories, and, in turn, what role those false memories had in convicting Scott Peterson.

I would also like to see more research completed by Loftus and others on the role of misinformation in police interrogations and some measures taken in the State Legislatures to forbid these practices and assign stiff penalties when they are used.