When witnesses get it wrong

Prof Graham Pike, part of the OU psychology Forensic Psychology Research Group, writes about the recent Hallam case. Eyewitness testimony is a major area of applied psychology and one that is covered in the modules you’ll take over your psychology degree.

The Innocence Project is a US based organisation that uses DNA testing to exonerate people that were wrongfully convicted of a crime. Of the 289 cases that they have successfully overturned, more than three-quarters involved misidentification by an eyewitness. For more than 30 years, research in psychology and the social sciences has documented just how unreliable eyewitness evidence can be, and demonstrated that even a witness who is completely confident can be completely wrong.

But it is not only in the US that unreliable evidence from eyewitnesses has led to wrongful convictions. In May 2012, and after having spent 7 years in prison, Sam Hallam successfully appealed his murder conviction. The original conviction was based largely on the evidence provided by two witnesses who said they had seen Hallam at the murder scene attacking the victim. Hallam’s QC (Henry Blaxland) claimed this evidence was “so manifestly unreliable that the appellant’s submission of no case to answer should have been allowed”. When interviewed by the police, Hallam provided an alibi, but this was not investigated.

As the US Innocence Project has overturned conviction after conviction, it has been tempting to see misidentification as somewhat of a distant problem. After all, it is only recently that individual states in the US have begun to provide guidelines concerning the construction and conduct of identification procedures, whilst here in the UK we’ve had the Police and Criminal Evidence Act since 1984! The Hallam case really brings home just how dangerous eyewitness evidence can be and just how careful our criminal justice system needs to be when dealing with it. Even though we have carefully constructed guidelines that were informed by social sciences research (download this PDF for more info), it is still possible for terrible miscarriages of justice to take place.

Graham Pike, Professor of Forensic Cognition, The Open University