Human Brains Linked Together for Thought Communication Over One Mile
Is it possible to link two brains together? Scientists say they've done it. It turns out that researchers use a brain-to-brain interface to allow pairs to play a "20 question" style game, which may demonstrate that two brains can be directly linked.
"This is the most complex brain-to-brain experiment, I think, that's been done to date in humans," said Andrea Stocco, one of the researchers, in a news release. "It uses unconscious experiences through signals that are experienced visually and it requires two people to collaborate."
In the experiment, the first participant wore a cap connected to an electroencephalography (EEG) machine that recorded electrical brain activity. The respondent was then shown an object on a computer screen. Then, the second participant saw a list of possible objects and associated questions. With the click of a mouse, the inquirer sends a question and the respondent answers "yes" or "no" by focusing on one of two flashing LED lights attached to the monitor, which flash at different frequencies.
A "no" or "yes" answer both send a signal to the inquirer via the internet and activate a magnetic coil positioned behind the inquirer's target head. But only a "yes" answer generates a response intense enough to stimulate the visual cortex and cause the inquirer to see a flash of light known as a "phosphine." The phosphine is created through a brief disruption in the visual field and tells the inquirer the answer is yes.
The researchers carried out the experiment in dark rooms located almost a mile apart. It involved five pairs of participants who played 20 rounds of the question-and-answer game. Each game had eight objects and three questions that would solve the game if answered correctly.
So what did they find? The participants were able to guess the correct object in 72 percent of the real games, compared with just 18 percent of the control rounds. Incorrect guesses in the real games could be caused by several factors, the most likely being uncertainty about whether a phosphene had appeared.
"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," said Stocco. "But it requires a translation. We can only communicate part of whatever our brain processes. 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 findings are published in the journal PLOS One.
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