Scientists have connected three people's brains together so they can play Tetris

Three people wearing brain-reading caps have successfully played Tetris using telepathy. That's my favourite sentence I've written from the past six months, and "the first successful demonstration of multi-person non-invasive direct brain-to-brain interaction for solving a task", according to the researchers.

This went down in an experiment from the university of Washington in Seattle, where two people mentally relayed the state of a Tetris game to a third participant - who could only see the block they were manipulating. Further reading reveals this is actually only an incremental step forward in brain-to-brain connectivity, and they were playing very slowly. It's still very cool.

I'll confess my thoughts ran away from me a bit when I first saw the headline. How are they communicating? What does it feel like to perceive a Tetris board through another person? How long until I can link brains with my Dota 2 team and become part of an unstoppable cyborg hivemind?

Quite a while, you'll be surprised to hear. The communication was all one way, with the two senders wearing electroencephalography (EEG) caps that recorded brain signals produced by their thoughts. They could send a yes or no message telling the recipient, wearing a transcranial magnetic stimulation (TMS) cap, whether or not to rotate the block in front of them. They did that by focusing on one of two flashing LED lights either side of their monitors, which had YES and NO written by them.

The EEG caps processed signals from the visual cortex, which were passed on to the receiver by magnetically stimulating their own visual cortex. If the senders looked at the YES LED, the receiver saw a flash of light. It's not the sci-fi scenario I couldn't help myself imagining, especially considering the two people wearing EEG caps had 15 seconds to transmit - and they sent their messages 8 seconds apart.

The scientists added another layer to the test, mind. They asked one sender to send the wrong information, so the receiver had to figure out which sender was trustworthy. They were told if they'd made the correct decision after each block, and succeeded "with an average accuracy of 81.25%". Five groups of three participated.

So, there was something different about the light perceived from a correct signal compared to a false one. I've been combing through the research paper looking for how they reckon they managed that, but surprisingly I haven't found any speculation as to what characterised those differences in the signal. There's plenty about how they hope these are the first steps towards a telepathically connected world though.

"The pursuit of such BBIs (brain-to-brain Interfaces) has the potential to not only open new frontiers in human communication and collaboration but also provide us with a deeper understanding of the human brain", it says.

Maybe one day the RPS hivemind will be exactly that.