Like HowStuffWorks on Facebook!

How to Play 20 Questions Without Talking

Whether we're talking, texting or holding up semaphore flags, it can seem impossible to truly share the essence of an idea without being misunderstood in some way.  So it makes sense that we would wish for telepathy, a process that would allow us to funnel our thoughts directly into one another's minds, without running them through the intermediary mangler of our language skills.

Well, place another tick in the column under “Technology's Attempts to Grant Our Weirdest and Most Impractical Wishes.” In recent years, several groups of scientists have successfully used computers and neurological interfaces to allow humans to share information between brains without language. Whether this actually brings us any closer to what we would recognize as telepathy remains to be seen, but the experiments are very interesting.

As we discussed in the Fw:Thinking video above, in 2014, researchers at the University of Washington published a study showing they were able to establish a technologically mediated, noninvasive brain-to-brain interface (BBI), which allowed one person to cause movement in another person's body, without speech, across the Internet. The basic interaction goes like this:

1. Person A sits in a room wearing an electroencephalography (EEG) cap, which detects and measures electrical activity in the brain.

2. Person B sits in a different room, positioned under a device that can directly stimulate parts of the brain by generating electromagnetic fields. This is called transcranial magnetic stimulation (TMS).

3. Person A thinks a thought: “Move my hand.”

4. The EEG cap reads the electrical activity of Person A's brain at that moment and translates it into data.

5. That data is sent through the Internet to Person B's room.

6. The data received causes the TMS coil to stimulate Person B's brain.

7. Person B moves their hand.

This was a fascinating feat, but since then, several of the same researchers have taken their experiments further. In a study published in September 2015, they explained that they had demonstrated this principle could be used to play a game along the lines of “20 Questions” between two rooms almost a mile apart. The interaction from the 2015 study went like this:

1. Person A, wearing an EEG cap, views an object. (Let's say it's a picture of a parakeet.)

2. Person B, who has a TMS coil positioned carefully over their visual cortex, selects a yes-or-no question about this object to send to Person A. (“Can this object fly?”)

3. Person A sees this question, and then gazes at one of two different LED stimuli to answer it. One is a “Yes” LED, and one is a “No” LED. The two stimuli show different frequencies of light, which cause different electrical patterns in the brain when viewed. The difference between these patterns can be detected by the EEG cap. (A parakeet can fly, so Person A would look at the “Yes” stimulus.)

4. The computer mediating the communication detects the answer, and sends the corresponding “Yes” or “No” to Person B.

5. If the answer is yes, the TMS kicks into full gear, pumping an electromagnetic field into Person B's visual cortex and causing Person B to experience a false sensation of light known as a “phosphene.” (Since the answer to the “Can it fly question?” question was yes, Person B receives a phosphene.)

6. By judging whether or not they received a phosphene vision, Person B learns something about the object in question. (It can fly.)

7. Repeat until the object is guessed.

This setup allowed participants in the experimental group to win 72 percent of games. In a control group where no genuine information was relayed, only 18 percent of participants correctly identified the object.

You may notice that despite the fact that information was being relayed without language, there is still a version of encoding and decoding taking place between the two participants; it's just not through traditional language. So it's hard to imagine how technology of this kind could actually be used to achieve anything like a Dreamfast in Jim Henson's "The Dark Crystal" or Spock's "Vulcan mind meld" on "Star Trek," where perfect understanding of another person's memories, beliefs and motivations can be downloaded almost instantly through some arcane process.

When asked about the future applications of this research, the researchers have pointed to potential therapeutic applications — for example, sending signals from the brain of a focused student into the brain of a student who has difficulty paying attention.

And for those worried that these experiments form a basis for technological mind-reading or mind-control, you can rest easy for the time being. The first thing to notice is that the information being shared from brain to brain is not especially complex; it's a sequence of coded bursts. At best, this could communicate information slowly and laboriously, through a system like Morse code. 

Another thing to notice is that these experiments require bulky, expensive equipment and the full cooperation of all participants. You couldn't expect to secretly attach a TMS device to someone's skull without their knowledge. But depending on how the technology develops, it is legitimate to ask questions about whether we want to live in a world where a stranger can make you see a vision of light or make you move your hand.

Of course they can sort of already do that today — they just have to talk you into it.

More to Explore