Technology measuring our knowledge may soon be used to help fight crime.
LISTEN ABOVE: Larry Williams talks to professor Robin Palmer about the future of 'brain fingerprinting'.
Forensic brainwave analysis is about to be trialled on prisoners after successful pilot studies.
The technology measures brainwaves, and analyses whether a person knows something about a particular incident, or not.
University of Canterbury law professor Robin Palmer said it could be a big tool for police.
He said it could be used by police interviewing suspects and informants in investigations, through to prisoners disputing their convictions.