New Study Shows How Subtle Cues Given During Interrogation Can Alter the Memory of Eyewitnesses


As readers may remember, in July of this year, the Los Angeles County Board of Supervisors agreed to pay Francisco Carrillo a civil rights settlement of $10.1 million for 20 years of wrongful imprisonment. (We reported on Franky Carrillo’s case here.)

Carrillo was sixteen when a Los Angeles County Sheriff’s deputy allegedly influenced a crucial witness to wrongly pick Carrillo as the shooter in a murder that the teenager didn’t commit, resulting in his conviction, and a life sentence.

Carrillo always insisted on his innocence, and he eventually persuaded a team of defense lawyers to take on his case and, in 2011, they secured his release. Forensic psychologist Scott Fraser became part of that team, and presented evidence at a Habeas hearing showing that the witnesses who initially couldn’t have seen what they claimed to have seen. (Five of the six original witnesses had already recanted their original testimony, The sixth invoked his Fifth Amendment right against self-incrimination.)

In the TEDx talk above, Fraser refers to the Carrillo case as he explains how the fallibility of human memory can affect eyewitness testimony.


Of course, in the case of Franky Carrillo, it wasn’t simply that the witnesses memories were inaccurate. Instead, the main witness was reportedly influenced by an LA County sheriff’s deputy who appeared to have decided that Carrillo was the shooter.

Then the newly reconstituted memory of the first teenage witness influenced five more teenagers who, after talking to their friend, suddenly believed that they too had seen Carrillo shoot the victim.

Recent years have produced a growing body of research regarding the ways in which certain kinds of interrogations can alter the memories of eyewitnesses, or produce false confessions in suspects.

For instance, there is research showing that giving an eyewitness “direct negative feedback” about what they remember having seen or heard, along with “suggestive questioning” can lead the eyewitness to change what he or she reports remembering.

Other studies have indicated that even non-verbal feedback can influence what a witness believes that he or she remembers.

Now a newly published study by Dr. Linda A. Henkel, who researches memory at Fairfield University in Connecticut, shows how certain kinds of “negative feedback” delivered in a pleasant, supportive manner by an interviewer can cause eyewitnesses to change what they report remembering about a crime they have witnessed.

In an article published in Psychology Crime & Law, Henkel explains that the study consisted of two separate experiments in which 229 participants—179 women and 50 men—were each shown a video depicting a crime. Then each witness/participant was interviewed twice about the video.

In the first interview, the witnesses were simply questioned about what they had seen or heard about the crime in the video.

Then, after that first round of interviews, according to Henkel, the questioner gave half of the participants “supportive negative feedback” about what they said they’d observed, while the other half of the witness/participants got “neutral feedback” about what they reported having seen on the video.

The supportive negative feedback might be “sympathetically suggesting why many people’s memory may be inaccurate.” Or the interviewer might subtlety but non-critically suggest that what the witness reported was wrong, and that he or she should try harder to remember correctly.

The results of the experiments showed that those participants given supportive negative feedback changed significantly more of their responses between the first and second round of questioning, than those who were given neutral feedback by the questioners. In other words, the memories of the group who received the negative feedback, no matter how pleasantly delivered, actually seemed to change between the first and second round of questioning.

The Crime Report also has a story about the study and notes that Henkel reported that “the feedback does not have to be as explicit as saying ‘You got a lot wrong,’ but can arise from implying that one’s report is unsatisfactory,” or even if the questioner suddenly becomes abrupt in their manner toward the participant.


The fact that, in approximately three-quarters of the cases of people exonerated in recent years by the Innocence Project, the convictions hinged on eyewitness testimony, suggests that the topic of eyewitness fallibility is important arena for additional research.

For instance, writes Henkel, “future research” is needed to “better understand whether, when people change their responses upon repeated questioning, they truly believe that the event happened the way they now claim.” Or if “participants had relatively low levels of confidence in their memories, and hence may have been responding with what they assumed or guessed might be the correct response, rather than relying on what they actually remembered.”

Nationally recognized memory researcher, Elizabeth Loftus of the University of California, Irvine, had this to say about the issue.

“Eyewitness testimony is very powerful and convincing to jurors, even though it is not particularly reliable. Identification errors occur, and these errors can lead to people being falsely accused and even convicted.

“Likewise, eyewitness memory can be corrupted by leading questions, misinterpretations of events, conversations with co-witnesses, and their own expectations for what should have happened. People can even come to remember whole events that never occurred.”

Yet, since we still depend heavily upon eyewitnesses in the legal arena, research like that of Henkel’s may help us better understand their uses, their limitations, and the nature of their potential corruptibility.

1 Comment

  • How can detectives influence witness memory, elicit false testimony and win a wrongful conviction?
    Just look at what LAPD NorthEast Detectives DiCroce and Carrillo did in the trial of Matthew Turner for a 2008 Highland Park gang shooting.
    The recently highlighted release of Francisco Carrillo after 20 years in prison and $10 million settlement from Los Angeles County for the role played by a Sheriff Deputy in his wrongful conviction is kid’s play compared to
    the dirty work done by the LAPD detectives that squeezed witnesses to supply erroneous identification testimony against Matthew Turner at trial.
    And when one of the teenage witnesses who was chaperoned to police lineups couldn’t identify a suspect – that didn’t stop Detective Jose Carrillo from taking the stand at trial and telling the jury the witness lied at the line-up and identified the suspect to him in private conversation as he drove the young man home afterwards.
    Sounds kind of crazy, doesn’t it?
    Just as crazy as LAPD detectives arresting the wrong suspect. Giovanni Ramirez, for the assault of Giant’s fan Bryan Stowe in the Dodger Stadium parking lot.
    Well – that was done by the same Dumbledore LAPD(Retired) Detective Jose Carrillo, who made an entire career out of manipulating suspect line-ups, coercing underage witnesses and filling in the holes by taking the stand himself against his own witnesses.
    In the next 20 years, his misdeeds and wrongful convictions will end up costing the taxpayers of Los Angeles an extra $10 – $20 million.

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