Scientists say they can read a person's
unconscious thoughts using a simple brain scan.
The scan picks up subliminal thought activity
Functional MRI scans plot brain activity by looking at brain
blood flow and are already used by researchers.
A team at University College London found with fMRI they
could tell what a person was thinking deep down even when the
individual was unaware themselves.
The findings, published in Nature Neuroscience, offer exiting
new ways to probe the subconscious, said experts.
In the experiment, Dr Geraint Rees and Dr John-Dylan Haynes
measured brain activity in the visual cortex - the part of the
brain that deals with information sent by the eyes - while
volunteers looked at different test objects on a computer
By looking at the functional magnetic resonance imaging
(fMRI) scan results, the scientists were able to predict what
had been displayed on the computer screen better than volunteers
When two images were flashed in quick succession, the
volunteers only consciously saw the second one and were unable
to make out the first.
But the brain scans clearly distinguished the patterns of
brain activity created by the "invisible" images.
Similarly, a separate study by Japanese researchers,
published in the same journal, found that when people were shown
stripes tilted in different directions, there were subtle
differences in the pattern of brain activity obtained by fMRI.
The scientists built a computer program to recognise these
different patterns and found they could predict what direction
stripes had been shown with remarkable accuracy.
When volunteers were shown a plaid pattern made up of two
different sets of stripes but asked to pay attention to only one
set, the program was able to tell which one the subjects were
Dr Rees said: "This is the first basic step to reading
somebody's mind. If our approach could be expanded upon, it
might be possible to predict what someone was thinking or seeing
from their brain activity alone."
Dr Adrian Burgess, from the department of cognitive
neuropsychology at Imperial College London, said: "The technique
is bringing out information that has not been available from MRI
"It could potentially be used to find out people's latent
attitudes and beliefs that they are not aware of.
"You could use it to detect people's prejudices, intuition
and things that are hidden and influence our behaviour."
He said it might be possible to dip into people's repressed
memories or even see people's hidden fears and phobias.
"That's a long way off, but it is exciting."