Photograph by John Burcham, National Geographic
Published October 30, 2013
A commonly held belief that traumatic childhood memories are accurate misleads judges and jurors in criminal cases, according to a scientific review released on Wednesday.
Neuroscience and behavioral research into memory cuts directly against confidence in eyewitness testimony expressed by police and jurors in surveys, writes psychologist Mark L. Howe of City University London.
"Memory often serves as the key or only evidence in the courtroom," Howe writes in Nature Reviews Neuroscience. Yet many police officers, judges, and jurors in North America and Europe "are naive when it comes to understanding how memories are formed, how they become distorted over time, and how stress and emotion affect remembering."
Until the age of eight or nine, most people don't have a sense of memory that is developed enough to reliably recall more than the bare outline of events, particularly stressful ones, the review concludes. (Also see "Memory: Remember This.")
Perhaps the most notorious criminal case involving issues of dubious childhood eyewitness testimony was the McMartin Preschool trial of the 1980s. The case involved sexual abuse accusations at a Manhattan Beach, California, day-care facility.
All charges were dropped at the end of the trial in 1990. A psychologist suggested that memories of abuse had been implanted in the minds of children by investigators, a view that swayed most of the jurors.
Nevertheless, despite what research has shown about the malleability of memory, law enforcement officials are still alarmingly overconfident about testimony from childhood, Howe suggests.
Memory develops slowly through infancy, behavioral research shows, with most memories before 18 months completely lost to people later in life, a phenomenon known as "infantile amnesia." Memories remain sparse and lacking in detail until age eight. (Also see "Braingames: Use It Or Lose It".)
That means that honest courtroom testimony by adults about early childhood events would contain few details. A richly detailed recounting of events is more likely have been embroidered or created by the witness, perhaps unconsciously.
Shortly after events, "although young children are frequently correct in the basic facts of what happened, their narratives do not contain many of the additional details," Howe says. Witness testimony that includes specifics—the color of someone’s clothes or the weather on a particular day—is probably suspect. Even true memories become distorted over time.
The belief that memories of stressful events are retained more vividly than others also goes against what psychologists have found, says Howe. "Overall, the fact that an event was stressful or traumatic is not a good predictor of a child's subsequent memory for that event."
Still, more than half of judges, jurors, and police officers in a 2006 survey agreed that "traumatic experiences can be repressed for many years and then recovered." Less than a quarter of memory experts agreed.
Overall, Howe writes that our everyday picture of memories as fixed and stable is wrong. Such beliefs about memory are fundamental, however, to the whole idea of eyewitness testimony in courtrooms. Partly for that reason, psychologists and neuroscientists have become increasingly critical of eyewitness testimony in the last decade.
National Geographic asked Howe to elaborate on some of the points he made in the review, which is part of a series on neuroscience and the law presented by the science journal. His written responses, lightly edited for clarity, follow:
How big a problem is it that adult witnesses are recounting childhood memories as testimony in the courtroom? Are many cases decided by eyewitness testimony of this type dubious?
All cases involving historic childhood sexual abuse involve memory evidence, and where there is no other corroborating evidence (e.g., medical records) it serves as the only evidence. So all cases of historic childhood sexual abuse are decided, in whole or in part, on memory evidence.
The issue, as discussed in the article, is the age at which memories were formed for the alleged abuse, the type of information contained in the complainant's narrative, the length of time this information has been in memory, and the intervening experiences that may have influenced memory during this interval.
What are the brain processes that make this kind of eyewitness testimony most unreliable? Is it the storage of memories? Or is it their retrieval? Or some combination?
It is a combination and has to do with the age at which information was encoded, how well that information can be stored, and what happens to that information during the decades of retention prior to testifying.
Do you see the remedy in educating law enforcement about the limits of this testimony? Or should there be policies limiting its use?
I view this as more of an education issue. When memory is the main or only evidence, those involved in the justice system (e.g., police and triers of fact) need to know how memory works because their naive beliefs about how it works are frequently wrong.
What do you see as the telltale signs of dubious testimony?
Because there is no litmus test discriminating true and false memories, and because decades-old memories encoded when we were children are often fragmented and decontextualized, whenever there is a worry about the extent of detail (particularly for peripheral information) and the content (particularly if there are concepts there that would not be known by a child of that age) of a complainant's narrative, then there are serious concerns about whether such memories can be used to convict.
You make the point that reconsolidation and reconstruction of memories takes place unconsciously, distorting memory. What does this say about all of our fondest memories? Are they at all reliable if we’re constantly burnishing them?
Difficult to say for certain, but my guess is that we should treat many of these memories with a (rather large) grain of salt.
There is considerable evidence showing that memory does not always serve us well if what we are trying to do is recapture an accurate or verbatim glimpse of the past. Indeed, we can often misremember even the core of events that have happened to us.
Memory serves us best by abstracting the relevant meaning from our experiences, not the exact details of every experience, and this allows us to form a worldview, a lens through which we interpret our present and anticipate the future.
Follow Dan Vergano on Twitter.
We should also add here that psychology is a "pseudo science" and always was questionable until they pushed to have it declared a science. One should study the history of this "science" from the point of view of how much horror has been inflicted upon humanity. The latest of course is "pill pushing" which can inflict more pain than the original problem. One needs to look at court cases where for example the prosecutions psychologist proclaims that the individual is absolutely sane, while the defense psychologist proclaims that the individual is totally and unequivically insane. The book that describes mental conditions is even in question by psychologists themselves. Why one should ask is a mental condition "cured" by any one of the various disciplines within psychology...eg. Freuidian, Behaviourism etc. The one common denomitor seems to be "listening" to what the individual has to say and a minister, friend or priest can achive the same results. Price controls should be placed upon the profession..some charge $500 per hour for their pseudo explanations.
In some ways the human brain can be thought of as a "tape recorder". It records EVERYTHING. The entire experience from BIRTH until death is accurately recorded and is retained in the unconscious. One problem is that life is experienced continuously and as it is recorded it blends in with past experiences. The second problem is that the younger a person is the less experience one has and therefore cannot recognize what the experience is all about and thefore cannot describe it because ones volcabulary has not developed sufficiently. As a child progresses in age experience and volcabulary expand. Therefore a child of three cannot express the experience of rape as well as a child of 7. The only reliable evidence is physical, and even that can be unreliabable as bruises can be made from illness, falling, banging, for example a child who "rocks" and while doing so bangs their head against the crib or a wall. Many individuals are in prison because courts allowed unreliable infomation sometimes influenced by social workers, relatives, friends or police who intentionally or not implanted false information to a child who only wants to please. Take a ton of sand, remove from it one grain and that grain represents what psychologists know about the human mind. Ask any of them to explain "telepathy"!
I think memories vary from person to person. I have excellent and some very vivid childhood memories. I can say they have not changed over the years. I remember colors of my clothes, places where things used to be in my house, patterns on material, even what kind of shoes I had. I even remember early thoughts that I didn't have the vocabulary yet to express.
@El Gabilon Nice!Cool!
@Heather Noe I agree with you. Clothes, places of items, not so much conversations. The blue green outfit I wore to Kennywood Amusement park, riding the trolley car through the city of Pittsburgh, including car changes, I was only 4. No family pictures of that one.
How to Feed Our Growing Planet
National Geographic explores how we can feed the growing population without overwhelming the planet in our food series.
The Innovators Project
Meet some of science's most important movers and shakers—from past and present.
Latest Photos Galleries
A family traces the trailblazers in the 1950s using original records