Reading the mind

Scientists can now predict what a person is seeing just by looking at their brain, even in the absence of conscious awareness.

Among the components of a scene recognised by visual areas of the brain are sloping grids of lines. Functional imaging reveals that different neurons respond to grids of different orientation.

By backward masking, researchers can eliminate conscious awareness of the orientation of a grid that a subject has been exposed to. Even so, distinctive patterns can be seen in a brain scan, so a researcher can predict which image the subject saw.

The brain has captured, subconsciously, information about a scene. Although the subject has no recollection, the image has been imprinted in the brain and can be 'read' by a researcher. In effect, scientists have managed to take a snapshot of someone's subconscious – a simple form of mind reading.

See also

• All in the mind: Searching for the neural basis of consciousness (Feature: 30 September 2005)