Fighting crime with brain scans
Promising but unproven brain fingerprinting research won’t prove people guilty but might ask defendants hard questions. Will Harvie reports.
"Criminals cannot hide when their brainwaves are willing to confess." Brainwave Science website
In 1977, Terry Harrington was arrested for the murder of a retired police officer in Council Bluffs, Iowa, US. Harrington had an alibi corroborated by several witnesses – they’d been attending a concert at the time.
But a teenage witness testified that he’d seen Harrington commit the crime. Other evidence was also presented and the jury convicted. Harrington was sentenced to life without parole.
Harrington was innocent and his exoneration after 24 years followed two distinct tracks. The first was a friendly stranger who got interested in Harrington’s case and investigated for years. These efforts eventually led a US$12 million compensation payment to Harrington and a co-defendant.
The second track might change criminal investigations and trials on a scale not seen since DNA evidence became common.
It’s called brain fingerprinting and a New Zealand team primarily based at the University of Canterbury is attempting to validate the technique – pioneered in the United States – for future use in interrogation rooms and courtrooms here.
Brain fingerprinting will not prove that a person is guilty, but it might ask defendants awkward questions, Professor Robin Palmer told a public meeting last week in Christchurch. The suspect will have a lot of explaining to do, he said.
The technique uses an electroencephalogram (EEG) test to detect electrical activity in the brain. Longstanding research has shown that about 300 milliseconds after the human eye sees information (objects, images or phrases), there is an involuntary brainwave response that indicates the human recognises the information. It’s called a P300 brainwave.
If the brain does not recognise the information, there is a different P300 brainwave response, Palmer said.
The technique is not a lie detector, the law professor said. Rather it detects whether the suspect retains knowledge – the sort of thing, for example, that only a person present at a crime scene would know. This evidence of knowledge may then lead to inferences of guilt or participation, he said.
A video presented at the public meeting illustrated how the technique works. A man convicted of theft relating to the manufacture of meth and two others not connected to the theft or the meth were separately strapped into an EEG machine.
All three were shown information about the theft, including that it was in a rural location and that meth precursor chemicals and a grain silo were present at the crime scene. The EEG picked up P300 responses from all three but only one showed an elevated P300 response.
He was man who had already pleaded guilty.
Only he had been at the scene and remembered features from the scene. The other two were familiar with grain silos, for example, but did not recognise the silo was important to the test.
In the case of Harrington in Iowa, the EEG test showed his brain did not recognise critical details of the murder scene but his brain did recognise details of his alibi.
In the end, a court accepted the validity of the brainwave technique but the science was not needed to exonerate him.
Brain fingerprinting remains unproven and the Canterbury team is investigating further, with funding from the NZ Law Foundation and others. A yearlong pilot project finished recently and the overall conclusion was that the ‘‘verification experiment results provide a solid platform for further research’’.
Others have plunged ahead. The technique was pioneered by Dr Larry Farwell, who left academia after discovering the apparent usefulness of P300 waves. He co-founded a company called Brainwave Science that sells the service, along with devices and proprietary software, to police forces in the US, India and elsewhere.
The company’s website claims the technique is 99 per cent accurate based on tests runs by the FBI, CIA and US Navy.
The technique could help in counter terrorism (did a suspect make a bomb and where?), national security, human and drug trafficking, border security and even immigration.
‘‘Criminals cannot hide when their brainwaves are willing to confess,’’ claims the website.
The New Zealand team is not willing to go that far. Brain fingerprinting has ‘‘potential’’ they say. They have visited Farwell in the US and he has visited New Zealand to support their research.
There are many unknowns, project scientist Professor Richard Jones of the New Zealand Brain Research Institute, told the meeting.
For example, would intoxication affect the test? What about autism, dementia, concussion?
Time will always have lapsed between the alleged crime and the test. How much will time matter? ‘‘We don’t know,’’ Jones told the public meeting.
There’s been little independent verification of the technique, he said, something the Canterbury team hoped to address. Funding applications have been lodged.
As a brain scientist, Jones said the technique looked ‘‘robust’’ and Farwell was the ‘‘real Mccoy’’.
The technique is ‘‘highly resistant to counter measures’’, he said.
Debra Wilson, project co-leader and associate professor of law at Canterbury, noted forensic science had a mixed role in criminal courts. A hundred years ago, the shape of a suspect’s skull was thought to be relevant to state of mind.
She also raised the right to silence. Nobody can be forced to speak. But a brain scan could be seen as a form of selfincrimination, she said. It could a type of technical confession.
On the other hand, courts accept drink-driving breath tests and DNA left at a crime scene as good evidence. Bits of humans can be used against defendants in courts. Are brain scans different?
Wilson’s role on the project was to investigate the legal, social and cultural aspect of brain fingerprinting.
She asked: Even if it’s accurate, is this something we as a society want to use?