London, May 11 (ANI): Brain scanners can also be used as lie detectors, according to US researchers.
Scientists at Stanford University claim it can help to know if a witness is lying when identifying a suspect in a crime investigation.
The experts could tell when a person recognised a mug shot by reading their brain waves.
Functional magnetic resonance imaging (fMRI) was used to observe brain activity during the memory recall task, Proceedings journal reported.
As part of the study, 16 volunteers were asked to study hundreds of faces in an images database.
Later, they were shown a series of pictures that included some of the faces they had seen earlier.
They were asked to identify the mug shots they recognised, while rigged up to the brain-scanning fMRI device.
The researchers noted distinct patterns in the brain activity that reflected what the individual was thinking.
Specifically, from the scans alone, they were able to tell if the volunteers recognised the faces as old or new and whether this recognition was accompanied by recollection.
However, the test was unsuccessful in distinguishing between subjects who accurately reported recognising a face and those who mistakenly claimed to recognise a previously unseen face.
"It was only as good as a person's memory and their memory may or may not be accurate," the BBC News quoted lead researcher Dr Jesse Rissman, as saying.
He said for the technology to be of use in a court room, it would need to tell you not just that the person was recalling a memory but that the memory was accurate.
Rissman added: "We can't tell from our data, because our participants were asked to make honest judgements, but if someone wanted to fool the test they might be able to."
He claimed that to withhold the identity of a guilty suspect, a witness could fixate on a novel image or think of something new that they planned to do that day, for example.
Also, to incriminate someone, the witness could think of a strong image from their past or remember a recent event, he said.
He ended: "These are things that would need to be checked. We need to do more work and plan to look at more in-depth memories and witness accounts. So the practical application is far off yet." (ANI)