So one of the issues is really just people’s misunderstanding about probability.<īut probability is one of those really weird areas. And so sometimes they do say, well, that’s then there’s too much doubt, the person wouldn’t be guilty. So for example, if there are five pieces of evidence about which they’re say 75% certain then they’ll, rather than think about overall we’re 75% certain, what they do is they really say okay well this piece of evidence, that’s 25%, this piece of evidence, that’s another 25%, this piece of evidence, it’s another 25, this piece of evidence, another 25. But what we’ve found is that many jurors do, if there’s degrees of doubt about particular pieces of evidence, rather than seeing that it’s the overall probability, they actually start to add them up. So the way jurors tend to think, we’ve found, is that for, say, one individual characteristic or issue about which they have doubt, if there were now five characteristics and they, for each of them they were 60% certain, in a probability perspective that means that overall their certainty is still about 60%. Say, again, rather than being 90% sure or 95% sure, they’re only about 60% sure. So the evidence presented by the prosecution is convincing except maybe there’s one piece of evidence that people have a significant degree of doubt. So, for example, imagine that there’s a piece of evidence that reduces the likelihood that an individual committed a crime, and say it reduces it to say 60 or 70% certainty.
One is that when we think about probability… For example, if you think about a trial where there’s a particular element where people might have some doubts. I think in general they struggle and I’ll give you two examples. And what that really means is that there’s no doubt that the individual has done it beyond really the smallest amount that a reasonable person could dismiss.ĭo you think that that’s something that the average person on the street will understand, I mean given that juries are made up of these ordinary people? Generally many of the legal instructions that jurors are provided by judges, they really struggle to understand those instructions and “beyond reasonable doubt” is a very good example because, particularly in the Western adversarial legal system, it’s probably the most important maxim which is that no-one should be convicted of an offence until they’re found guilty beyond reasonable doubt. Do jurors understand what that means? And in fact what does it mean? Jim, I was fortunate enough to hear you speak at a dinner organised by the Victorian Juries Commissioner Paul Dore this year and I was particularly interested in your comments about “beyond reasonable doubt”. Professor James Ogloff, welcome to the User Experience podcast.< He’s the director of the Centre for Forensic Behaviour Science at Swinburne University of Technology in Melbourne, Australia.Īnd this year he received the Order of Australia award. He has received awards from the Canadian Psychological Association and the Australian Psychological Association. He has an expertise in forensic psychology, forensic mental health, mental health law and the assessment and management of offenders. It’s a bit hard to do justice in a brief introduction to my guest today. This is Gerry Gaffney with the User Experience podcast. Still from “Runaway Jury” (New Regency Express) Transcript