Witness's memories are crucial to the law - but is memory more fallible than is usually believed?

We all know what we remember, don't we? Especially when it comes to witnessing a violent crime.

Now, scientists are increasingly questioning whether we understand just how unreliable human memory can be.

In this week's Law In Action we ask whether that creates risks for justice.

Faulty memory has been responsible for innocent people being implicated in crimes they didn't commit, according to Elizabeth Loftus, a professor of law at the University of California, Irvine.

"We now … have hundreds of cases of wrongful convictions. People who have spent five and ten and fifteen or more years in prison for crimes they didn't do," she tells the programme.

Experimenting with memory

Professor Loftus says it is surprisingly easy to convince people that they remember something that never happened.

In one experiment, she asked her students to help convince their younger siblings that when they were little they had been lost in a shopping mall.

When questioned later, around a quarter of the subjects then recalled such an incident as if it had actually happened to them.

Now a report prepared for the British Psychological Society and the Law Society aims to provide guidelines to help courts assess the reliability of memories.

Is science suspicious of memory?

Professor Martin Conway of Leeds University, the main author of the report, says scientists tend to regard memory with considerable suspicion.

He tells the programme that most memory researchers today would not accept an account of memory without additional evidence.

"... if you give me a description of a robbery you've just seen and that's all we have to go on, then for a memory researcher that couldn't be judged to be either a reliable or an unreliable account. We just simply wouldn't know."
Martin Conway

Conway says there is a tendency for people involved in the criminal justice system to influence witnesses, intentionally or unintentionally.

This might be by asking leading questions or by reinforcing memories while recapping what a witness has said.

Memory and justice

Law In Action visited Peel Centre, the police college in Hendon, North London, to see how officers are trained to avoid the pitfalls of memory when they first take evidence.

Instructors there said they are very careful to make officers aware of the risks of using leading questions.

Some in the justice system are wary of introducing memory researchers as expert witnesses in trials.

"Frankly, I think this is a faintly ridiculous suggestion," says Gerald Butler QC, a former judge.

"Juries are there in order to use their common sense and when it's the situation that you must weigh up a witness's evidence and decide whether … he or she has a good and factual recollection of what has taken place, this is essentially a matter for the jury."

Coming Up

In next week's Law In Action we'll be asking if Zimbabweans can look to the law to resolve their problems.

If you have thoughts on any of the topics we've covered, or any other legal issues, Law In Action would like to hear from you.

You can contact us by email at lawinaction@bbc.co.uk or by post at Law In Action, BBC White City, Wood Lane, London W12 7TS or you can call us on 020 8752 5646.

Memory - Your Thoughts

We had a strong response from listeners to the report on memory and the law. Here are some of the comments:

Several times the mantra was repeated that things had been working reasonably OK for several hundred years, that juries were perfectly capable, when expertly guided by advocates and judges, to establish the reliability of memory. This completely missed the point about the fundamental nature of human memory – that if it is not supported by objective evidence it is highly fallible, whatever jurors, the judge, or the witness themselves think. It has been amply demonstrated that it is possible for false memories to be created, whether deliberately or otherwise, which are as reliable as any “true” memory. The witnesses involved can be as convinced of a “false” memory as any other. None of this is to argue that lawyers should be blindly led by scientists; quite the reverse. It’s the very lack of understanding of scientific method and evidence among much of the legal profession that is a problem here, and the evidence of this programme is that this could be pervasive.

Steve Jones

I am not an expert, but I respect new findings that challenge our assumptions when they are backed by solid research. I have been fascinated more than once by the changes in our understanding on memory as something fixed and constant which have been covered by other Radio 4 programmes, such as the book discussed on Start the Week some months ago, "Memory" by Harriet Harvey Wood. I suppose the big giveaway here is that I am not a lawyer. Perhaps that dismisses my opinion. Perhaps a qualification one needs in order to be a lawyer is a determination not to accept the possibility there may be something new to learn from science that could help our work? I prefer to hope that there is a range of opinion among lawyers and that as the report suggests, jurors could also be helped by having a clearer understanding of memory.

Joelle Marlow

To lose your right to freedom and face years of incarceration for something of which you are innocent because the courts have chosen to exclude sound expert evidence on memory is a travesty of British justice. As Professor Martin Conway stated, "Most researchers today would not accept an account of memory without additional evidence". Neither should the courts.

Madeline Greenhalgh, Director, The British False Memory Society

Law In Action was broadcast on Tuesday 17 June 2008 at 1600 BST on BBC Radio 4.