Three brains may be better than one JACK GUEZ/AFP/Getty Images

Using only their thoughts to communicate, three people wearing brain-reading caps worked together to play a game of Tetris. This is the first instance of more than two people collaborating through brain-to-brain communication.

“Our experiment can be regarded as the first proof-of-concept demonstration that multiple human brains can consciously work together to solve a task that none of the brains individually could,” says Rajesh Rao at the University of Washington in Seattle.

In the experiment, three people combined minds to play a game of Tetris. Two of the team were tasked with sending information about the state of the game to the third player who actually decides which moves to make.


The two people sending information wear electroencephalography (EEG) caps to record the brain signals produced by their thoughts, and the receiver wears a transcranial magnetic stimulation (TMS) cap that delivers the information to their brain.

The senders can see the entire game board, and so have to tell the receiver whether to rotate the block or not. The receiver only sees the current block, not the state of play. The senders communicate with the receiver by focusing their attention on one of two flashing LED lights on either side of a computer monitor, which had the words YES and NO on either side of the screen.

Where they focus their attention can be extracted by processing signals from the visual cortex. To pass this information to the receiver, their occipital lobe – the brain’s visual processing centre – is stimulated magnetically when the senders thought ‘yes’, causing the receiver to see a flash of light.

The senders have 15 seconds to send their decision, and the two decisions are received 8 seconds apart. “The real Tetris game would be too fast for the current version of BrainNet,” says Rao.

The team also tested whether the receiver could judge if the directions from the senders were accurate, by asking one sender to give bad information. The receiver then had to learn which sender was more reliable to judge whether or not to rotate the block.

The receiver was told after each move whether they made the correct choice. Five groups of three people played this modified Tetris game, rotating the block so that it fit into the row below with an average accuracy of 81.25 per cent, including the trials where one sender gave the wrong instruction.

Hiveminds

Rao says many brains working to solve one problem in this way may be the future. “Extrapolating this idea, one could regard networks of connected brains as humanity’s solution to overcoming the biological limits on human brain evolution,” he says.

“We are probably in a pre-hivemind phase,” says Giulio Ruffini at NeuroElectrics in Barcelona. This new work is an incremental improvement on current technology, he says, but it’s a step forward for non-invasive brain-to-brain communication.

His colleague, Ana Maiques, says the most practical use for this technology would be helping people who cannot speak, either because of neurological or physical limitations. “Or, you could use many brains to compute a difficult problem. Or to do something abstract like write a song. But I think that’s wishful thinking,” she says.

Attempts to merge human brains with computers, either with non-invasive techniques like Rao’s or surgically implanted chips, are being undertaken by companies like Facebook and Neuralink, a raft of start-ups, and the US military’s research arm, DARPA. None have yet introduced a product available to the masses that can stream thoughts from your brain to your computer and back, but they’re likely not too far off.

Don’t go thinking you’re going to incept an idea into a pal’s mind any time soon, though. Facebook and DARPA have both said their early goals are to allow people to interact with software programs or type without using their hands. A mind-meld videogame might may be years off yet.

Reference: arXiv, arxiv.org/abs/1809.08632