In a recent experiment, scientists had a person send a one-word email to another person using nothing but their brains, a little extra hardware, and the internet.
This is likely the closest that people have ever gotten to telepathy — although, admittedly, it's still not very close. The researchers, in their PLOS ONE paper, called it the "realization of the first human brain-to-brain interface."
To do this, the researchers basically used existing technology in novel ways. On the message-sending side, they took a mind-reading electroencephalograph, or EEG (which has previously been used to harness a person's thoughts to make a living rat's tail move). On the message-receiving side, the scientists used transcranial magnetic stimulation (which has been used to, among other things, make people's memories stronger).
Still, the experiment doesn't mean we're on the cusp of being able to read each other's minds. For one, the process of sending the message was extremely complicated, and not very practical. This telepathy research could end up with almost no utility — or it could be what everyone is doing in a few decades. In any case, here's how they pulled it off.
How this latest "telepathy" experiment worked
The experiment involved a number of steps. Here's how they did it.
1) Create a binary code for simple words: The researchers encoded the messages "hola" and "ciao" into a binary series of "0s" and "1s." In this particular case, they used a code called a Bacon cipher as their translation guide.
2) Hook the sender up to an EEG: The researchers then connected the sender of the message to a bunch of electrodes in order to read his/her brainwaves. The technique here is called electroencephalography (or EEG) and is frequently used in both research and medicine.
3) Transmit the binary code by having the sender think about their hands and feet: Next, the sender imagined moving his or her feet for 0s and hands for 1s. These are big enough differences in brainwaves that the EEG could pick up the difference.
(The researchers used a bit of a cheat at this point: they gave the sender a visual cue: a circle moved on a computer screen in relation to their brainwave output. However, in the future, it's possible this could be replaced by brain-only feedback mechanisms. Or, with enough training, people might not need feedback at all.)
4) Send the message long distances over the internet: The EEG brain signals were translated into 0s and 1s and then sent via email to the receiving person.
5) Transmit flashes of light to the message-receiver from a very special magnet: The person receiving the message was hooked up to a device that used a magnet outside the head to produce electrical signals within the brain, influencing its activity.
In this case, the magnet was set up to activate part of the visual cortex — and produce the perception of a flash of light. (This happened even though nothing had actually stimulated the eyes. In fact, the person was blindfolded just to make sure.) It's a pretty weird phenomenon, called a phosphene.
The receiver knew that a flash meant "1" and no flash meant "0." People could then translate the 1s and 0s back into words — "hola" or "ciao." Telepathy complete!
This is currently a very impractical form of communication
The total speed of communication using this process was 2 bits per minute. That's roughly one millionth the average internet speed in the US. And that meant it took roughly 70 minutes just for one person to say "hola" or "ciao" to another.
Also, not surprisingly, the experiment wasn't perfect. The error rate ranged from 1 to 15 percent, depending on the exact trial. So yes, telepathic communication already contains typos. Then again, they weren't using any autocorrect feature. At least not yet.
But could it ever become useful?
Sometimes it's difficult to see how something this inefficient — more than an hour of time, and two sets of crazy-weird electronic headgear, just to say one word — could ever become something useful. But it's not crazy to think that this could someday become more practical.
This research was mostly a demonstration that the concept works. In the future, both the technology and the users could get better at sending messages.
For example, other researchers have used a different type of brain-activity reading technology, fMRI, to guess, with some accuracy, what shapes people are looking at or what type of object they were dreaming of — a building, a car, a book, et cetera. Another study used electrodes implanted within the skull to get one rat to tell another rat what lever to press for a reward. These both required far more involved and less practical technology.
But these types of brain-interfacing tech have been getting more sensitive, smaller, smarter, and more portable over time. And they'll probably continue to do so, whether you think telepathy is a good idea or not. There will, of course, be limits to what these devices could do, but we really have no idea what they are yet.
Additionally, people could meet the technology halfway — learning how to control their thought output better and how to interpret artificial electromagnetic inputs. The mind can be an astonishingly flexible tool. In the future, people might not have to translate their words into binary in order to get them across. Maybe they could picture what the letters look like, or imagine what the words sound like when spoken aloud. Or they could even send out non-verbal thoughts.
Nothing's for certain. This technique for communicating might never become useful. Or one day we might find it more handy than email or texting. For now, this is just a very early step.
Further reading: It's worth noting that there's a dispute over who actually conducted the first demonstration of human brain-to-brain communication. A different group had already performed a study similar to this one, but it wasn't published in a journal. Emily Waltz over at IEEE Spectrum went into the controversy, if you'd like to know more.
Correction: The study that got a rodent's tail to move was in a rat, not a mouse.