How much faith do you put in the justice system? Most people would claim a dose of healthy cynicism towards the legal process and, in particular, solicitors, but in the population as a whole, a lot of that seems to be just bravado. Jacqueline Wheatcroft – a forensic psychologist from the University of Liverpool – has been researching the psychology of the courtroom for over a decade. In one of her studies, which familiarised members of the general public with cross examinations, the focus groups’ feedback was eyebrow-raising. “They just did not believe that the barrister would try to manipulate or trick them into saying things that were wrong.”

“All the scientific problems with the justice system have one common factor: people.”

You may scoff at that, but it’s a serious problem. For all the solemn imagery that the scales of justice and gavel conjure in our mind – that of unbiased, dispassionate justice – there are plenty of known problems with the courtroom. So many, in fact, that it’s difficult to know where to start, until you narrow it down to the common factor that all of the issues have in common: people.

See related Chernobyl and Fukushima disasters: What happens to nuclear exclusion zones when humans leave? The science of scientific denial Parapsychology: When did science give up on paranormal study? We humans, packed with our own years of experience and internal biases, are extremely unreliable. We’re also, as it turns out, worryingly easily swayed, and often less by cold, hard facts than what conveniently fits our understanding of the world around us. Acknowledging this isn’t a way of criticising the integrity of individuals, it’s about putting the justice system beyond reproach. Or, as Tim Valentine, professor of psychology at Goldsmiths University, told me: “ Confirmation bias is just a ubiquitous feature of human cognition, so we should design a system to control it.”

Valentine is talking about eyewitness testimony – and, specifically, the unreliability of it. “Identification is error prone however we want to look at it – the one exception being where people are identifying people they know well, but, of course, that is not usually the case.”

Nonetheless, “eyewitness testimony” is often lauded as the holy grail because we give our senses far more credence than we should, scientifically speaking. “If an eyewitness stands up in court and says ‘that’s the man who attacked me, I remember his scary eyes,’ – that’s really convincing to juries. You feel sympathy with the witness and believe it. We find it compelling.”

Compelling it might be, but reliability is a totally different thing, and a number of studies have attempted to correlate witness confidence with accuracy, and none of them have been terribly reassuring. “Witnesses can be confident and wrong. They may not have perceived things as they actually happened,” explained professor Amina Memon, chair of psychology at Royal Holloway University. Various factors can come into play, from poor viewing conditions to inappropriate questioning or the time elapsed between the event and the recall. “That can vary regardless of how reliable the witness appears to come across.” In other words, appearance, credibility and trustworthiness don’t always correlate, but juries expect them to anyway.

“A number of studies have attempted to correlate witness confidence with accuracy, and none of them have been terribly reassuring.”

In the case of witness identification, Valentine has seen similar issues. “There is a relationship between confidence and accuracy, if measured properly – if you measure it at the time they make their identification. The problem is we don’t do that, we just listen to what they say in the courtroom.”

“If that witness has had feedback telling them that the person they’ve identified is the police suspect, or they may just infer it because they’re asked to go to court, then that feedback enhances the confidence. But it enhances it even if they’re wrong,” Valentine added.

Wheatcroft agrees: “The general public think that someone who is highly confident, and delivers in that way, must be right, but actually it doesn’t always go hand-in-hand.” This is bad enough on its own, but her research shows that questions can be phrased in such a way that elicits a higher level of confidence than should actually be felt. Does this mean that barristers might – intentionally or unintentionally – phrase questions in such a way as to influence a witness’ response? “Not might. They do.”

“If you look at lots of trial transcripts, you can see clearly the amount of leading questions that are constructed to witnesses in order to prompt a particular response, which they often get,” explained Wheatcroft.

“Questions can be phrased in such a way that elicits a higher level of confidence than should actually be felt.”

“Judges can intervene when a barrister asks a leading question, if they think the premise is wrong, or they think it’s unreasonable or overbearing, but, in reality, they tend not to.” Her latest paper suggests the prohibition of leading questions, but what immediately jumped into my head here is brash US court dramas, where defence and prosecution lawyers keep intervening. That’s not entirely Hollywood fiction: “Their lawyers will jump in and be more animated,” said Wheatcroft.

“In America, the training of witnesses is part and parcel of the legal process, while it’s forbidden in the UK.”

In America, the training of witnesses is part and parcel of the legal process, while it’s forbidden in the UK. “There is a significant difference there in how they might approach things, because, over there, witnesses will be trained and have gone through several roleplays on what kind of questions might be asked.” That sounds like a significantly more damaging system, but actually there’s a kind of backwards logic there: if everyone is trained to sound polished and convincing, then everyone – at least theoretically – should come under the same scrutiny, rather than running the risk of juries conflating unreliability with anxiety.

So before we even reach the ears of the jury, all kinds of unreliable factors have come into play. However, the twelve men and women brought in to deliberate on innocence and guilt are not without their own psychological baggage, either. In theory, the quantity of the jury should mean that any existing biases and prejudices should be watered down, right? “There’s a question of how representative a jury might be, and what kind of background they’re coming from, and what kind of case they’re listening to, so it really can depend on many factors,” says Wheatcroft. The Ministry of Justice is more upbeat on the subject, and its study, Are Juries Fair?, is quite positive about the outcome, reporting little evidence of racial bias or a reluctance to convict in certain case types.

It does, however, suggest that more can be done with regards to training members of the public for jury duty effectively, and technology has been something of a double-edged sword in this respect. There have been a number of high profile cases where jury members have disregarded instructions and looked up people involved in the case on the internet. The temptation to do this has probably always been there, but never before has it been pocket-sized and available anywhere with a phone signal. Are Juries Fair? suggests a quarter of jurors surveyed look up case information while the trial is ongoing, despite being told not to. Ironically, trying to become better informed is one of the worst ways to bring out unintended biases, and, unsurprisingly, the justice system is cracking down on this. One juror has even been sentenced to eight months in prison for contacting a defendant through Facebook, and another couple have been sentenced for looking up case details.

“The good news is that there is an appetite for change in the system. The bad news is that, as with all aged institutions, change can be slow and lumbering.”

Technology colliding with the archaic institution of the courtroom can cause a few problems, not least in our slavish devotion to technology. Eyewitness accounts are weak, as mentioned earlier, but even when corroborated with camera footage, they’re far from perfect. “If you show people good quality images and ask them to pick out the same person, if the images were taken by different cameras, the error rate is around 30% under ideal conditions,” explained Professor Valentine. Naturally, ideal conditions don’t reflect the majority of cases, with predictable results.

The good news is that there is an appetite for change in the system – in some areas, at least. The bad news is that, as with all aged institutions, change can be slow and lumbering. “We do things reasonably well in this country, and we have improved it, and the situation is far worse in America than it is here,” said Valentine. That said, Valentine’s call for “blind” video line-ups (where the police officer doesn’t know whether the person identified is the suspect or not) has met some resistance from the Home Office as a perceived attack on police integrity. “I’m not suggesting police officers or witnesses are being corrupt or dishonest – it’s just our natural psychology.” Just a side-effect of being human. “This isn’t a radical idea: clinical trials of drugs have been run blind for years.”

Wheatcroft’s latest paper – the one on the prohibition of leading questions – has just been published in the Criminal Law Review journal. “We’ve been able to identify these types of questions, and we know they’re damaging because we’ve got all this literature and all these peer reviewed papers that show this, so it’s time to make a significant change – to prohibit a certain kind of question.”

“There’s certainly an appetite for change at the moment. We’ll see where it goes.”

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Images: Sam Howitz, Michael Coghlan, Beth Cortez-Neavel, Robert Couse-Baker, Ronnie Macdonald, Surrey County Council and Elliott Brown used under Creative Commons