Talking about MRI scanners in court

fMRI in court: a pack of lies?

Brain imaging’s role in lie detection

Tom Ziessen, Engaging Science Manager at Wellcome, made a short documentary about using functional magnetic resonance imaging (fMRI) for lie detection. Nancy Wilkinson interviewed him to find out about his search for the truth.

Why did you decide to make this film?

I worked at the Science Museum in London for a while, and while I was there I worked on a project on the brain – looking at neuroscience and the many ways it can impact society. This is where I first came across fMRI [a technique that measures brain activity by detecting changes in blood flow] used for lie detection. I now look after the grants awarded for public engagement at Wellcome, and I thought research into fMRI as a lie detector could be helpful to Wellcome and relevant to my job now.

Where did you research the topic?

I chose to go to India and the USA. In India they already use a form of lie detection in courts. In the USA, the first time that an attempt had been made to bring lie detection into courts was in 2010, so it was a good time to go. In India a lot of people I wanted to meet refused to meet me, and the people I did meet generally refused to let me film them. They didn’t want to look bad on film and they didn’t want to look like they were doing dubious work. It was a bit of a brick wall. In America, I started with the two companies who offer fMRI as a lie detector: No Lie MRI and Cephos. I also tried to talk to the people involved in the cases in which they tried to use this evidence in court or people who had commented on this in the papers. In America, fMRI is not used in court yet, and I’m not sure about how useful it might be in a legal setting.

What did you find out in India?

I have seen absolutely zero evidence that the lie detection techniques used in India work at all. [In India, many forms of lie detection – not just fMRI – are used.] I think it’s absolute nonsense, and it is used a lot more often than we think. When I went to a forensic science lab in Bangalore they said they had used lie detection techniques on 1,000 people; it is just horrendous.

What research has been done?

Most of the tests have been quite simple, and they’ve been with volunteers who have been told to tell a lie so they may not reflect a real-life situation. We also don’t know whether everyone’s brain is the same: we don’t know whether a psychopath’s brain is the same as someone else’s, and that’s very difficult to measure. We need a lot more evidence, especially evidence that is more applicable to real-life situations. We need tests that show what happens when the lie is not something someone has been prompted to do.

What happened in the employment law case featured in the film?

A witness was being tested, using fMRI, to see whether he was telling the truth or a lie: he had allegedly been instructed to refuse someone work after she complained about sexual harassment. The judge ruled that the jury is supposed to act as the lie detector, and the judge didn’t want any new science in the court. But we know juries are not good at detecting whether someone’s lying or not, so fMRI could have given a better indication of whether that witness was telling the truth and helped them win the case.

Do you think this compares to other techniques?

It doesn’t compare to DNA testing. It’s far less certain. However, polygraph testing [using a device that measures changes in blood pressure, pulse and the amount of moisture on skin to test whether someone is lying] is still used a lot, just not in courts as much. But the polygraph’s accuracy is not good. We know you can be trained to beat a polygraph test and that they’re not very good, but they are still used. In some ways, it is as much about the interrogator or interviewer in a polygraph as it is about the technology. fMRI is more about the technology.

What do you think is the future for fMRI as a lie detector? 

Some lawyers that I met want it, and some don’t. Lots will be against it until there have been some decent-sized studies of it. I also think it’s possible that this could be seen on programmes such as ‘The Jeremy Kyle Show’, and that’s really quite worrying!

Lead image:

A clip from the film.

Tom Ziessen


Questions for discussion

  • If you were a judge, would you allow evidence from fMRI lie detection in your court?
  • Can you search the internet to find two other forms of lie detection used around the world and describe them?

About this resource

This resource was first published in ‘Inside the Brain’ in January 2013 and reviewed and updated in November 2017.

Neuroscience, History
Inside the Brain
Education levels:
16–19, Continuing professional development