DNA evidence can confuse jurors

Sydney, Mar 29 (ANI): A large number of jurors suffer from the "white-coat syndrome", and end up getting swayed by DNA evidence in court and find an accused person guilty, according to a study.

This tendency to be overwhelmed by experts could mean that there is a danger jurors place undue weight on scientific evidence.

However, a 20-minute presentation to jurors significantly increases their understanding of DNA and its use in criminal trials, and will make them more sceptical and reduce the likelihood they will convict.

"The greater understanding increases their objectivity about the evidence of the experts. When there is greater understanding of the evidence, there are fewer miscarriages of justice," the Sydney Morning Herald quoted the lead researcher, Jane Goodman-Delahunty, as saying.

In fact, this even caught defence lawyers and judges, she said.

"I think because DNA evidence has attained a status where the underlying science is no longer so controversial that many defence lawyers no longer challenge it and show its fragilities," she added.

People failed to appreciate the potential for laboratory error or contamination and for DNA to be accidentally transferred, she said.

She also said that the concept of "random match probabilities" - the likelihood of a coincidental match between the crime scene sample and a person - was poorly understood.

And people forgot to consider that in some places the matches were based on only eight points of comparison, while in the US up to 13 points were matched, increasing the reliability.

Conducted by Professor Goodman-Delahunty, the research has also found that frequent viewers of CSI-style television shows are among people with the lowest understanding of DNA science.

People with low understanding of DNA convicted at a rate of 75 per cent in mock trials, while those with greater knowledge recorded only a 42 per cent conviction rate, she said.

Overall, studies have shown juries are three times more likely to convict in identical cases if DNA evidence is presented at a trial.

Courts should introduce short presentations to juries and not shy away from using multimedia, which had been found to be effective in increasing the understanding of people with low DNA knowledge and among the younger generation, she said.

The findings of the study have been released by the Australian Institute of Criminology. (ANI)