In one version, the traumas which marked the victim’s body indicated that the attacker may have been right-handed. In an alternative version, the damage suggested a left-handed attacker. If the accused person is left-handed, this pushed up the number of jurors who thought he was more probably guilty and so on. The final section of her study, the psychologist added another detail – that the accused person had been convicted of an analogous crime previously. Guilty, not guilty? Although I cannot recall off the top of my head the exact percentage leap – the jurors veered radically and illogically towards voting ‘guilty’. All of this, simply on the evidence that the attacker was left-handed and the man in the imaginary dock had been convicted of something similar before. The study was small, the numbers not terribly statistically significant, nevertheless it suggests that the old legal saw is probably empirically verifiable – the prejudicial influence of adducing evidence of prior convictions outweighs its probative value. All the more interesting, because the view does not emanate from some crusty, claret-soaked QC – but from science-totting psychologist.
At present, this rule is enshrined in the Criminal Procedure (
All of this is relevant because Kenny MacAskill has asked the Scottish Law Commission to examine the admissibility of prior convictions. The ever-helpful Criminal Justice
While the Herald and Scotsman host rather bland responses, the Times is joyously, rip-roaringly hostile. In general, I sympathise far more strongly with the critics here than with the proponents of change. Given MacAskill's reference to the Law Commission, this issue will be floating about for a while, with discussion documents, consultations and the like to follow. Consider this one, pre-emptive, negative response.