Can psychologist and psychiatrist expert witnesses be trusted to know how memory works?

Psychologists and psychiatrists are frequently called on to provide expert testimony in court. When the memories recalled by an alleged victim, suspect and/or eye-witness become an explicit issue, is it safe to assume that the psychologist or psychiatrist in the expert role will have up-to-date scientific knowledge about the reliability of memory? Worryingly, a new Norwegian study suggests not.

Annika Melinder and Svein Magnussen surveyed 858 psychologists and 78 psychiatrists about their understanding of memory. This was tested through the participants' agreement or not with 12 statements about memory function. Melinder and Magnussen were particularly interested in whether the 117 psychologists and psychiatrists in their sample who act as expert witnesses in court would perform better on the survey than those who don't.

The participants who don't act as expert witnesses scored an average of 6.49 on the survey; the expert witnesses in the sample did no better, scoring an average of 6.68. The silver-lining was that the expert witnesses performed marginally better on those survey items that pertained to clinical practice; they were more likely to recognise: the relative unreliability of children's recall compared with adults; that the age of earliest first memories is typically from three years and up; that traumatic memories from childhood cannot be completely forgotten only to be recovered later in therapy; that memories for dramatic events typically lead to better memories; and the fact that perpetrators who say they've repressed memory of their crimes are almost certainly lying.

Overall, however, Melinder and Magnussen said the expert witnesses' performance on the survey was "not very impressive". They fear this could have "catastrophic consequences" in court. "There are numerous well-known examples in the USA and European judicial systems of false convictions of innocent persons arising from the misguidance of the court by the testimonies of psychiatric and psychological expert witnesses on the reliability of witness memories," they said.

A complication with surveys of this kind is that they are premised on the idea that the science of memory is mature enough for there to be a consensus position on the issues raised. Melinder and Magnussen claim that the "correct" answers in their survey are based on expert surveys, meta-analyses, and research reviews. However, they admit memory science "does not have a metric gold standard".

It's notable that The Psychologist magazine in the UK has recently hosted a disagreement between psychologists who act as expert witnesses in court. In their article, one group claimed that more detailed auto-biographical memories are typically less reliable (this concurs with the third item on Melinder and Magnussen's survey), but the second group wrote in to say that this claim is overly simplistic. With such public disagreements between experts, perhaps it is no wonder that the current study found variability in psychologists' and psychiatrists' beliefs about memory.

A final note – writing in the New York Times this month, the psychologists Christopher Chabris and Daniel Simons argue that "The science of memory distortion has become rigorous and reliable enough to help guide public policy" and they highlight a report released by The National Academy of Sciences this year: "Identifying the Culprit: Assessing Eyewitness Identification" which distils the latest research on the fidelity of memory.