How much should the courts rely on a person’s memory? Today’s report by the British Psychological Society has put memory to the test – and found it wanting.

Research that illuminates the deficiencies of memory is clearly welcome: courts and those who work in them can only benefit from knowing how memory is fallible and varies according to the age of the witness, the kind of event recalled, how long ago it took place and any questioning by police or lawyers to elicit recall.

The failings of memory cannot be avoided, but the key question is how evidence is used and the extent to which courts rely on it. Getting the balance right between too much reliance and too little is difficult. So many key points in civil and criminal trials swing on the accuracy, reliability and honesty of human evidence.

Professor Martin Conway, the main author, is right to call for more caution over using memory evidence that is uncorroborated. Cynicism over “recovered” memories of child-sex abuse led to the coining of “false memory syndrome”. But without any other evidence, such allegations would not succeed. Judges already give careful guidance to juries when relying on memory.

Professor Conway, however, also urges greater use of memory experts to advise courts on when and to what extent a memory may be credible. Such changes would not, in my view, bring significant improvements. The use of large numbers of memory experts would add to the cost and length of trials, and lead to many unwarranted acquittals. Where memory is an important issue, there is nothing now to stop counsel calling an expert witness to help the court.

The criminal justice system already has many good protections against unfair convictions. A criminal trial requires the case to be proved “beyond a reasonable doubt”. That is a high standard: if there is significant doubt about the memory of a key witness, the prosecution will fail.

Gary Slapper is Professor of Law at the Open University

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