Telepathy is the supposed Extra Sensory Perception ability to read someone else’s mind at a distance. Whilst humans do not have that ability, brain-computer interaction researchers at Stanford have just made the high tech version a virtual reality.

It has long been know that by using brain implants or electrodes on a person’s head it is possible to tell the difference between simple thoughts. Thinking about moving parts of the body gives particularly useful brain signals. Thinking about moving your right arm, generates different signals to thinking about moving your left leg, for example, even if you are paralysed so cannot actually move at all. Telling two different things apart is enough to communicate – it is the basis of binary and so how all computer-to-computer communication is done. This led to the idea of the brain-computer interface where people communicate with and control a computer with their mind alone.

Stanford researchers made a big step forward in 2017, when they demonstrated that paralysed people could move a cursor on a screen by thinking of moving their hands in the appropriate direction. This created a point and click interface – a mind mouse – for the paralysed. Impressively, the speed and accuracy was as good as for people using keyboard applications

Stanford researchers have now gone a step even further and used the same idea to turn mental handwriting into actual typing. The person just thinks of writing letters with an imagined pen on imagined paper, the brain-computer interface then picks up the thoughts of subtle movements and the computer converts them into actual letters. Again the speed and accuracy is as good as most people can type. The paralysed participant concerned could communicate 18 words a minute and made virtually no mistakes at all: when the system was combined with auto-correction software, as we now all can use to correct our typing mistakes, it got letters right 99% of the time.

The system has been made possible by advances in both neuroscience and computer science. Recognising the letters being mind-written involves distinguishing very subtle differences in patterns of neurons firing in the brain. Recognising patterns is however, exactly what Machine Learning algorithms do. They are trained on lots of data and pick out patterns of similar data. If told what letter the person was actually trying to communicate then they can link that letter to the pattern detected. Here each letter will not lead to exactly the same pattern of brain signals firing each time, but they will largely clump together,. Other letters will also group but with slightly different patterns of firings. Once trained, the system works by taking the pattern of brain signals just seen and matching it to the nearest clumping pattern. The computer then guesses that the nearest clumping is the letter being communicated. If the system is highly accurate, as this one was at 94% (before autocorrection), then it means the patterns of most letters are very distinct. A letter being mind-written rarely fell into a brain pattern gap, which would have meant that letter could as easily have been the pattern of one letter as the other.

So a computer based “telepathy” is possible. But don’t expect us all to be able to communicate by mind alone over the internet any time soon. The approach involves having implants surgically inserted into the brain: in this case two computer chips connecting to your brain via 100 electrodes. The operation is a massive risk to take, and while perhaps justifiable for someone with a problem as severe as total paralysis, it is less obvious it is a good idea for anyone else. However, this shows at least it is possible to communicate written messages by mind alone, and once developed further could make life far better for severely disabled people in the future.

Yet again science fiction is no longer fantasy, it is possible, just not in the way the science fiction writers perhaps originally imagined by the power of a person’s mind alone.

– Paul Curzon, Queen Mary University of London, Spring 2021.