Two scientific teams this year patched together some well-known technologies to directly exchange information between human brains.

The projects, in the U.S. and Europe, appear to represent the first occasions in history that any two people have transmitted information without either of them speaking or moving any muscle. For now, however, the “telepathy” technology remains so crude that it’s unlikely to have any practical impact.

In a paper published last week in the journal PLOS One, neuroscientists and computer engineers at the University of Washington in Seattle described a brain-to-brain interface they built that lets two people coöperatively play a simple video game. Earlier this year, a company in Barcelona called Starlab described transmitting short words like “ciao,” encoded as binary digits, between the brains of individuals on different continents.

Both studies used a similar setup: the sender of the message wore an EEG (electroencephalography) cap that captured electrical signals generated by his cortex while he thought about moving his hands or feet. These signals were then sent over the Internet to a computer that translated them into jolts delivered to a recipient’s brain using a magnetic coil. In Starlab’s case, the recipient perceived a flash of light. In the University of Washington’s case, the magnetic pulse caused an involuntary twitch of the wrist over a touchpad, to shoot a rocket in a computer game.

Neither EEG recording nor this kind of brain stimulation (called transcranial magnetic stimulation, or TMS) are new technologies. What is novel is bringing the two together for the purposes of simple communication. The Starlab researchers suggested that such “hyperinteraction technologies” could “eventually have a profound impact on the social structure of our civilization.”

For now, however, the technology remains extremely limited. Neither experiment transmitted emotions, thoughts, or ideas. Instead they used human brains essentially as relays to convey a simple signal between two computers. The rate as which information was transmitted was also glacial.

Safety guidelines limit the use of TMS devices to a single pulse every 20 seconds. But even without that restriction, a person can only transmit a few bits of information per minute wearing an EEG cap, because willfully changing the shape of their brain wave takes deliberate concentration.

By comparison, human speech conveys information at roughly 3,000 bits per minute, according to one estimate. That means the information content of a 90-second conversation would take a day or more to transmit mentally.

Researchers intend to explore more precise, and faster, ways of conveying information. Andrea Stocco, one of the University of Washington researchers, says his team has a $1 million grant from the WM Keck Foundation to upgrade its equipment and to carry out experiments with different ways of exchanging information between minds, including with focused ultrasound waves that can stimulate nerves through the skull.

Stocco says an important use of the technology would be to help scientists test their ideas about how neurons in the brain represent information, especially about abstract concepts. For instance, if a researcher believed she could identify the neuronal pattern reflecting, say, the idea of a yellow airplane, one way to prove it would be to transmit that pattern to another person and ask what she was thinking.

“You can see this interface as two different things,” says Stocco. “One is a super-cool toy that we have developed because it’s futuristic and an engineering feat but that doesn’t produce science. The other is, in the future, the ultimate way to test hypotheses about how the brain encodes information.”