Court of personality

When trainee chef Essayas Kassahun was stabbed to death on the St Luke’s estate in East London in October 2004 during a melee involving a large group of youths, eyewitness evidence became a vital part of the police investigation. One witness identified a youth named Sam Hallam from a line-up, while another identified him during interview. Mr Hallam was subsequently convicted and sentenced to life imprisonment, but after serving seven years of his sentence, the conviction was quashed. The evidence of both eyewitnesses, it emerged, was ‘unreliable’. Unreliable eyewitness testimony is regularly cited as the biggest contributor to miscarriages of justice, and is a major factor in three-quarters of all wrongful convictions in rape and murder cases. One reason for eyewitness error is the circumstances surrounding an incident. In the Hallam case, for example, the incident unfolded quickly, a weapon was involved, it was distressing and some of the perpetrators had their hoodies pulled up to hide their faces. Recollection of an incident can also be influenced by others if, for example, a witness discusses the event with someone else afterwards, particularly other witnesses. One witness in the Hallam case initially told police they had seen a “black man brandishing a baseball bat” at the scene. Despite this, they later picked out Mr Hallam (who is white) from an identification parade. In cross-examination during the trial, the witness admitted they had selected Mr Hallam – who was known to the witness – after hearing a rumour that he was involved. A clearer understanding of what makes an eyewitness reliable, therefore, could potentially have a significant impact on the workings of the judicial system. Lee Curley, a pre-doctoral researcher in decision-making science at Edinburgh Napier University, and colleagues Jennifer Murray and Dr Rory MacLean, lecturers in psychology at the university, conducted a study into these “variables”. “I was interested in eyewitness testimony and most of the research had been into the sort of variables that the police could control, such as the way line-ups are presented. After scanning the literature, it seemed that personality was an area that had been neglected,” explained Mr Curley. The research suggested that people who were strong in one specific personality trait appeared much better at recognising what they witnessed at a crime scene than those who were weaker in that trait. This result, believes Mr Curley, could potentially enable judges and juries to differentiate between eyewitnesses who are likely to be right from those who might be less reliable. In the study, a group comprising 40 men and 40 women were given a common test for the five recognised dimensions of personality: extraversion, neuroticism, openness to experience, agreeableness and conscientiousness. They were then shown a film in which two men robbed a woman. The group was then given misleading information and told it was a summary of the film clip. Following this, they had to complete a ‘recognition’ sheet, agreeing or disagreeing with statements about what they had seen. “I scored whether they recognised what was in the information sheet or what they had seen in the video,” said Mr Curley. “If they recognised what they had seen in the video it was scored as correct and if it was from the misinformation sheet it was scored as a false memory. Then I followed that up to see if the results correlated with any of the personality traits.” The results showed that individuals who were ‘high’ in the personality trait of openness to experience were more accurate eyewitnesses. Mr Curley says at this stage, the results from the study demonstrate a correlation rather than a cause: this means the researchers can say that levels of openness relate to correct recognition in a way that other personality traits do not. No other personality trait was found to have either a positive or negative relationship with eyewitness testimony. “The more open individuals were, the more likely they were to