Two Humans Link Their Brains To Play 20 Questions


University of Washington
If you could eschew the telephone, and instead
wear a cap that allowed you to share your
thoughts with someone else, very far away,
would you? It may be a moot point now, but
there may come a time in the not-too-distant
future when it isn’t, largely due to the work of
Andrea Stocco and his team at the University of
Washington’s Institute of Learning & Brain
In this latest round of Stocco’s research, two
people were successfully able to transmit their
thoughts to each other over the Internet,
completing a game of questions-and-answers.
“This is the most complex brain-to-brain
experiment, I think, that’s been done to date in
humans,” Stocco said. “It uses conscious
experiences through signals that are experienced
visually, and it requires two people to
As with previous experiments conducted by
Stocco and his team, the experiment takes place
between people in separate locations.
One person, the responder, was shown an image
on a screen. The other participant, the inquirer,
then sent yes or no questions by clicking on them
with a mouse. The responder, wearing an EEG
cap that monitors, captures and translates brain
activity, answered by staring at one of two
flashing LEDs attached to the monitor, which
flashed at different frequencies.
These answers were captured, translated and
sent via the Internet to the inquirer, where a it
was transmitted to their brain using transcranial
magnetic stimulation via a magnetic coil
positioned behind their head. By using TMS to
stimulate the visual cortex, the inquirer was able
to see a flash of light known as a phosphene for
“yes” answers. For “no” answers, the inquirer
sees nothing and is therefore able to proceed.
The experiment was conducted in two dark
rooms almost a mile apart, with five pairs of
study participants, each of which played 20
rounds of the game, 10 real games and 10 control
rounds. Each game consisted of eight objects,
with three questions for each object that would
solve the game if answered correctly. For the
control games, an undetectable plastic spacer
was placed between the magnetic coil and the
inquirer’s head to block the TMS.
Making sure to correct for any possible means of
cheating, such as blocking the test subjects’
hearing, and repositioning the magnetic coil for
each round, the participants were able to
successfully able to guess the correct object for
72 percent of the real games, compared to 18
percent of the control games.
There were several reasons for the incorrect
guesses in the real games, the most likely of
which was interpreting the phosphene as
something not seen with the eyes, but the brain.
The responder not knowing the answers,
hardware problems, or focusing on both flashing
lights rather than one could also account for

University of Washington
With a $1 million grant awarded to the team last year, they have been able to broaden their research. Another area they are looking into is transmitting brain states, such as from an awake person to a sleepy one, or from a focused student to one who has ADHD.

“Imagine having someone with ADHD and a neurotypical student,” said co-author Chantel Prat, a faculty member at the Institute for Learning & Brain Sciences and a UW associate professor of psychology. “When the non-ADHD student is paying attention, the ADHD student’s brain gets put into a state of greater attention automatically.”

This also feeds into the notion of “brain tutoring”, which the team is also exploring. This could be simply transferring information from teacher to student, but it also could involve transferring signals from a healthy brain to one that is developmentally impaired, or affected by a stroke.

“Evolution has spent a colossal amount of time to find ways for us and other animals to take information out of our brains and communicate it to other animals in the forms of behavior, speech and so on. But it requires a translation.

We can only communicate part of whatever our brain processes,” Stocco said.

“What we are doing is kind of reversing the process a step at a time by opening up this box and taking signals from the brain and with minimal translation, putting them back in another person’s brain.”

The paper on this latest round of experiments can be found online, published this week in the journal PLOS One.

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