Dr Debra Wilson being prepared to take a simulated EEG knowledge-detector test Dr Farwell debriefing Dr Wilson at monitor Test in progress Professor Robin Palmer

Using brainwaves to help to solve crimes might sound a bit like something from the Jetsons - but could soon be a reality for investigators.

Canterbury University is leading a project that is looking at the potential to use the technology as legally acceptable evidence.

The technology already exists, but is facing an uphill battle to be recognised by both scientists and lawmakers.

The director of clinical legal studies at Canterbury University, Professor Robin Palmer, says the tests use a technique called brainwave analysis.

“The project we’re working on is not really a brain scan project, it’s really a brainwave project; it’s an adaptation of the EEG [electroencephalogram] to detect electrical waves in the brain, and by detecting those waves you can tell whether a person has knowledge of certain things or not.

“So it’s a knowledge detector rather than a lie detector.”

When the brain recognises something which it knows, or has seen, it creates a spike or a peak. If someone doesn't recognise or know something, the line is flat.

So if someone is shown something that only a perpetrator of a crime would know about, the brain instantly responds.

“You can't not have that spike, when the memory or knowledge is already imprinted on your brain," Prof Palmer says.

Information about a crime is divided into three categories: target information that anyone involved or associated with a crime would know about; probe information, which would be information that only the perpetrators would know about; and irrelevant information.

“You would need to work quite cleverly in terms of making sure you're presenting quite precise images that relate to a crime - so you would be talking about things which aren't public knowledge and that haven't been seen by a lot of people.

“Equally it can prove someone's innocence too - if you show them distinct images or ask distinct questions and there is no spike, then there's every chance the person you're suspecting of the crime is the wrong person.”

So why isn't this being more widely used by police around the world?

In the US, the polygraph industry is a strong and powerful one, which is reluctant to see new technology introduced.

This new technology will be trialled in New Zealand in November this year.

Prof Palmer says there is interest from police in New Zealand about using this technique alongside other methods.

“Traditionally New Zealand is more forward-thinking than other countries and open to adopting new technology. They see it more as another tool they add to their investigation techniques rather than quackery.”