user: Given the task definition, example input & output, solve the new input case.
In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.
Example: A photo series on the popular Humans of New York Facebook page may have went viral and captured the nation’s attention last Tuesday, but for Daniel Kang, the post really hit home. 
  
 When Kang, a junior studying computer science at the University of Michigan, heard that the refugee pictured and his family were relocating to his hometown of Troy, Mich., he said he knew he had to help. 
  
 “I was really inspired by how intelligent he was and I knew a lot of people wanted to welcome him, so I thought, why not it be me?” he said. 
  
 On the Humans of New York Facebook page with over 16 million likes — including comments from President Obama — the seven-part picture series’ captions detail one Syrian scientist and his family’s tale of loss after a missile strike destroyed their home, forcing them to to flee to Turkey, now with plans of coming to the United States. 
  
 “Everything ended for us that day. That was our destiny. That was our share in life,” the scientist said. Battling stomach cancer, the loss of a home, career and seven family members, the man, whose name remains confidential to protect his identity as a refugee, expressed his hope for a new life in the United States. 
  
 “I learned today that I’m going to Troy, Michigan,” he said. “I know nothing about it. I just hope that it’s safe and that it’s a place where they respect science. I just want to get back to work. I want to be a person again. I don’t want the world to think I’m over. I’m still here.” 
  
 Knowing that refugees come to the United States with little more than they can carry, Kang quickly organized a crowdfunding campaign to help establish the man in his new home. 
  
 In four days, the GoFundMe page has raised over $16K in donations from over 700 people. On Saturday afternoon, actor Edward Norton also began a fundraiser for the scientist, raising even more for the refugee who says he “just wants to be a person again.” 
  
 “The response has been overwhelmingly positive,” said Kang. “A lot of people thanked me for doing a nice thing but I really feel like I was doing what anyone else would have done.” 
  
 Kang said he’s received many messages from people expressing their gratitude, those who want to reach out to the man personally, as well local companies interested in working with the scientist. This includes invitations to lecture at local colleges, research job opportunities and potential help from local medical facilities in treating the man’s stomach cancer. 
  
 “There’s definitely a lot of interest in helping him out,” he said. 
  
 The biggest concern, said Kang, are those skeptical of how the money will reach the man. 
  
 Kang, who has successfully crowdfunded in the past, is working closely with GoFundMe, the local refugee relocation agency Lutheran Social Services of Michigan, and is in communication with the Humans of New York staff to make sure all funding goes to the scientist. 
  
 In the end, Kang said he just hopes the scientist receives the welcome he deserves. 
  
 “If I could talk to him right now, I’d just tell him how sorry I am for everything he’s been through and that he’s coming to a great place. One of the things he said that resonated with me the most is that ‘I hope Troy is a place that appreciates science.’ 
  
 I’d say out of all the cities in Michigan, Troy is the best place to raise a family, be a scientist and we can’t wait to have him.” 
  
 Oona Goodin-Smith is a student at Oakland University and a member of the USA TODAY College contributor network. ||||| I saw this story on one of my favorite sites, Humans of New York, and it moved me to tears. This man has suffered profound loss that would crush the spirit of many people and yet he still passionately wants a chance to contribute positively to the world. If we don’t welcome people like this into our communities and empower his dream of making an impact with his life, then we’re not the country we tell ourselves we are. Let’s reject the 'anti-human’ voices that tell us to fear refugees and show this man and his family what Americans are really made of. Let’s show that a country built by the energy and dreams of immigrants still believes in brave people who come here with hope for better life. 
  
 Everything we raise here will go to help this family so that the father can get the medical treatment he needs to live and pursue his work, and his family can build a new stable life after their tragedy, and…as the Scientist beautifully expresses…to support his dream of contributing to the world. 
  
 Thanks to Humans of New York for sharing these stories. Thanks to the team at CrowdRise for putting this together and figuring out how to get even the credit card transaction fees covered so we can get the maximum to the family. 
  
 Thanks to everyone who rallies together to create the power of the crowd. If enough of us kick in the price of two frappucinos, we can probably transform the experience of this family and show them that life can deliver healing and kindness, not just heartbreak. 
  
 Thanks to Benevolent, all donations are tax-deductible. We will work with Benevolent to use all donated funds to help this family and will seek to use any excess or unused funds to help the other 11 profiled in the HONY ‘Syrian American’ series. 
  
 Edward Norton ||||| DETROIT, MI -- Moved to tears by a Humans of New York feature on a Syrian refugee fleeing to Metro Detroit, Hollywood actor Edward Norton launched an online fundraiser that had raised nearly $450,000 for the widower and his four children as of Thursday afternoon. 
  
 "I didn't hear about it, but I want to thank him very much from the humanity perspective," the man told NBC News after hearing about the fundraiser's success. "There are people outside who need that money much more than me." 
  
 The man asked NBC to refer to him as "Abu Ammar," a fake named used to protect his relatives who remain in Syria. He's known to many on the Internet simply as "The Scientist," which is also his profession. 
  
 The refugee's family was scheduled to arrive in Troy, a Detroit suburb, Thursday. He and four surviving children spent the last two years in Instanbul, Turkey. They fled civil-war-torn Syria after the man's wife and one of his daughters were killed in a missile attack on April 6, 2013. 
  
 His is one of 12 families featured by Humans of New York and cleared to resettle in the U.S. 
  
 "I learned today that I'm going to Troy, Michigan," the man told Humans of New York. "I know nothing about it. I just hope that it's safe and that it's a place where they respect science. I just want to get back to work. I want to be a person again. I don't want the world to think I'm over. I'm still here." 
  
 The story made rounds throughout the Internet and even garnered a response from President Barack Obama's official Facebook page: 
  
 As a husband and a father, I cannot even begin to imagine the loss you've endured. You and your family are an inspiration. I know that the great people of Michigan will embrace you with the compassion and support you deserve. Yes, you can still make a difference in the world, and we're proud that you'll pursue your dreams here. Welcome to your new home. You're part of what makes America great. 
  
 ,Norton, known for his roles in movies like "Fight Club" and "Birdman," wrote in the description of his online fundraiser: 
  
 If we don't welcome people like this into our communities and empower his dream of making an impact with his life, then we're not the country we tell ourselves we are. Let's reject the 'anti-human' voices that tell us to fear refugees and show this man and his family what Americans are really made of. Let's show that a country built by the energy and dreams of immigrants still believes in brave people who come here with hope for better life. 
  
 (6/7) “I had no problems before the bombing. I think the cancer came from my sadness and my stress. It’s in my... Posted by Humans of New York on Tuesday, December 8, 2015 ||||| ISTANBUL — The grieving refugee who touched hearts as "The Scientist" on the Humans of New York blog only mustered a brief smile when told that a Hollywood star had helped raise $450,000 for him. 
  
 Hours before flying to Michigan to start a new life in the U.S. on Thursday, the cancer-stricken Syrian civil engineer glanced down. 
  
 "I didn't hear about it, but I want to thank him very much from the humanity perspective," he said after NBC News revealed the crowdfunding appeal. Oscar-nominated actor Edward Norton was moved to tears after reading the refugee's biography on the photography site last week and launched the fundraiser. 
  
 "There are people outside who need that money much more than me," The Scientist said, displaying the sort of compassion and humility that helped his story go viral. 
  
 The Scientist, who asked NBC News to refer to him as "Abu Ammar" to protect family in Syria, said his life was shattered by a bomb that killed his wife and daughter just under three years ago. 
  
 He was later diagnosed with stomach cancer, and has had to care for five remaining children. 
  
 They include a teenage son, who is still reeling after watching his mother die, and a daughter who carries inside of her shrapnel from the attack on April 6, 2013. 
  
 "When a bomb drops you don't know where it comes from," he said. "There is no question our lives changed after that ... 180 degrees. I am mentally tired, in overwhelming sadness." 
  
 “ As long as there are good people in the world … then we can stop this bloodshed” 
  
 On Thursday, Abu Ammar and four of his children flew to Troy, Michigan, as part of a United Nations refugee resettlement program. 
  
 For about two years, the family had been living close to destitution in Turkey. But the drive to succeed still lingers, Abu Ammar said. 
  
 "I've had ambitions since I was a child, and right now I'm still that same child with the same ambitions," he said. "But I still have a message — sometimes when I'm talking to myself I say, 'No, I'm not supposed to die. I need to live long enough to realize my message to humanity.'" 
  
 Abu Ammar's story on Humans of New York, a popular blog started in 2010 that spawned a bestselling book, prompted an outpouring of compassion. Even President Barack Obama contributed, calling Abu Ammar and his family an "inspirations" on HONY's Facebook page. 
  
 "Yes, you can still make a difference in the world, and we're proud that you'll pursue your dreams here." Obama wrote. "Welcome to your new home. You're part of what makes America great." 
  
 Last night President @BarackObama wrote a very sweet welcome note to the scientist in Tuesday's story. pic.twitter.com/ZGrn3gOdR7 — Brandon Stanton (@humansofny) December 10, 2015 
  
 Norton, who starred in "Birdman," "Fight Club" and "American History X," set out to help pay The Scientist's medical expenses. 
  
 "This man has suffered profound loss that would crush the spirit of many people and yet he still passionately wants a chance to contribute positively to the world," Norton wrote. 
  
 The resettlement of Syrian and Muslim refugees in the United States is controversial, especially in the aftermath of attacks by Islamic extremists in Paris and San Bernardino. Some politicians — notably GOP presidential hopeful Donald Trump — have called for a ban on Muslims entering the country. 
  
 Abu Ammar told NBC News he didn't know anything about the debate over Muslims and immigration raging in the U.S. He also didn't have a solution to the war raging in his home country. 
  
 "I don't like to get into politics because I am a man of science, and I can separate science and politics completely," he said. "But as long as there are good people in the world, and everyone looks into his or her conscience, then we can stop this bloodshed." 
  
 Abu Ammar added: "No one benefits from people dying, and wars overall never benefit anybody — so let's hope God can help everyone and put out this fire." |||||
Output: A Syrian refugee whose moving story went viral earlier this month starts his new life in Troy, Michigan, on Thursday, NBC News reports. The refugee—who wants to keep his real name out of the media to protect family members still in Syria—is known as "The Scientist" on the blog Humans of New York, where he was first profiled. "I learned today that I’m going to Troy, Michigan," The Scientist told HONY. "I know nothing about it. I just hope that it’s safe and that it’s a place where they respect science." According to MLive, The Scientist left Syria in 2013 after a bomb killed his wife and one of his daughters. Since then, he's been diagnosed with stomach cancer and was barely scraping by in Turkey. Despite being "in overwhelming sadness," he and his surviving children are hoping for a new start in the US, he tells NBC. Thanks to his story—which even got the attention of President Obama—The Scientist will have some help to get that new start. NBC reports actor Edward Norton was moved to tears after reading The Scientist's story and started a crowdfunding page that has raised nearly $450,000. "I didn't hear about it, but I want to thank him very much from the humanity perspective," The Scientist says. "There are people outside who need that money much more than me." A Michigan college student was also inspired to help after hearing The Scientist would be moving to his hometown, according to USA Today. His fundraising page has raised more than $16,000. "I’d say out of all the cities in Michigan, Troy is the best place to raise a family, be a scientist, and we can’t wait to have him," Daniel Kang says.
This is a good example. The output correctly summarizes the articles.

New input case for you: UW researchers have conducted what is believed to be the first experiment to show that two brains can be directly linked, allowing one participant to guess correctly what the other is thinking. 
  
 Brain scientists at the University of Washington have used an old-fashioned parlor game in a novel way to prove that two people’s brains can be linked across the Internet — an experiment that sounds like it was ripped from the pages of a science-fiction novel. 
  
 The experiment is believed to be the first one to demonstrate that two brains can be directly linked to allow one participant to correctly guess what the other is thinking. 
  
 Researchers say melding two minds has the potential for a vast range of applications. For example, it might allow for the transfer of information from a healthy one to a damaged one. Or it might allow an alert person to transmit that brain state to somebody who is sleepy, or struggling to pay attention. 
  
 “What we wanted to establish is that it is possible to use this rudimentary brain-to-brain collaboration … to solve a common problem,” said Andrea Stocco, an assistant professor of psychology and a researcher at the Institute for Learning & Brain Sciences at the UW. 
  
 The research was published Wednesday in the journal PLOS ONE. The brain-science investigations are funded by a $1 million grant from the W.M. Keck Foundation. 
  
 Researchers used “20 Questions,” a popular guessing game in which one person thinks of an object and the other tries to guess what it is with a series of 20 or fewer questions that can only be answered “yes” or “no.” 
  
 In the experiment, two participants played the game in rooms a mile apart on campus. One participant wore an electrode-studded cap connected to an electroencephalography (EEG) machine to pick up signals from the brain. 
  
 The other wore a cap with a magnetic coil positioned over the part of the brain that controls the visual cortex. 
  
 The player wearing the electrode cap picked an object, and the player wearing the electric coil used a computer mouse to select from a list of questions to get more information about the object. The electrode-capped player signaled to the questioner whether the answer to the question was “yes” or “no” simply by looking at a flashing light that indicated the answer. A “yes” sent a signal to the questioner; a “no” sent no signal at all. The signal was transmitted via the Internet. 
  
 If the answer was yes, the brain activity in the first player’s brain delivered a signal to the electric coil worn by the second player, which translated into a visual interruption or flash of light known as a “phosphene.” 
  
 Stocco said it took trial-and-error to position the magnetic coil so that it reliably transmitted a signal to the player asking the questions. And not everyone saw the same visual interruption. 
  
 “I consistently saw lines,” Stocco said. “Some saw lightning bolts, blobs or shapes.” 
  
 Stocco said the success of the experiment took researchers by surprise. 
  
 “We knew in theory it could work,” he said. “We wanted to know how well it could work.” 
  
 Subjects arrived at the correct answer in the “20 Questions” game 72 percent of the time; to do that, they answered more than 90 percent of the questions correctly. In other words, they saw the visual interruption, and interpreted it as a “yes.” 
  
 Five sets of participants played 20 rounds of the game — a mixture of 10 real games and 10 control games, in which no visual signal was sent at all. Participants guessed the correct answer only 18 percent of the time in the control games. 
  
 It’s not the first time Stocco and his fellow researchers have delivered a brain-to-brain signal over the Internet. Two years ago, Stocco and computer-science professor Rajesh Rao conducted an experiment in which Rao transmitted signals from his brain to Stocco, causing his finger to twitch, involuntarily. 
  
 At the time, researchers said they believed it was the first time two human brains had been directly connected in this manner. However, some neuroscientists dismissed the experiment as a publicity stunt. 
  
 In the finger-twitch experiment, Stocco was not consciously moving his digits, said Chantel Prat, researcher and faculty member at the brain science center. In the new experiment, the questioner “can actually consciously experience the information transfer.” The new experiment advances the science because “two people work together to problem solve,” she said. 
  
 Stocco said researchers hope they’ll eventually be able to transmit more complex signals, such as shapes rather than simple flashes of light. 
  
 In the 20 Questions experiment, “the brain is trying to make sense of a signal that normally doesn’t exist,” he said. “The brain is saying, ‘I don’t know what this thing is, but I think it’s a line.’ If we can control that with more precision, we could make a shape, or an object.” 
  
 If scientists could figure out how to transmit shapes between two brains, it might eventually allow people to collaborate on problem-solving in a completely novel way, he said. 
  
 Stocco said there are other applications for the science, too. 
  
 For example, researchers know how to measure patterns of brain activity to tell whether somebody is paying attention. One day, scientists may be able to capture those brain patterns and transmit them to a person whose mind wanders, such as a student trying to overcome Attention Deficit Hyperactivity Disorder. 
  
 Or perhaps one day, you could record the electrical impulses that pulse through your brain when you are at the peak of performance, and use that to wake up your brain at a later state, when your attention is flagging. 
  
 “It could be a new frontier of self-help,” Stocco said. ||||| UW team links two human brains for question-and-answer experiment 
  
 Deborah Bach News and Information 
  
 Imagine a question-and-answer game played by two people who are not in the same place and not talking to each other. Round after round, one player asks a series of questions and accurately guesses the object the other is thinking about. 
  
 Sci-fi? Mind-reading superpowers? Not quite. 
  
 University of Washington researchers recently used a direct brain-to-brain connection to enable pairs of participants to play a question-and-answer game by transmitting signals from one brain to the other over the Internet. The experiment, detailed today in PLOS ONE, is thought to be the first to show that two brains can be directly linked to allow one person to guess what’s on another person’s mind. 
  
 “This is the most complex brain-to-brain experiment, I think, that’s been done to date in humans,” said lead author Andrea Stocco , an assistant professor of psychology and a researcher at UW’s Institute for Learning & Brain Sciences . 
  
 “It uses conscious experiences through signals that are experienced visually, and it requires two people to collaborate,” Stocco said. 
  
  
  
 Here’s how it works: The first participant, or “respondent,” wears a cap connected to an electroencephalography (EEG) machine that records electrical brain activity. The respondent is shown an object (for example, a dog) on a computer screen, and the second participant, or “inquirer,” sees 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 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 “ phosphene .” The phosphene — which might look like a blob, waves or a thin line — is created through a brief disruption in the visual field and tells the inquirer the answer is yes. Through answers to these simple yes or no questions, the inquirer identifies the correct item. 
  
 The experiment was carried out in dark rooms in two UW labs located almost a mile apart and 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. The sessions were a random mixture of 10 real games and 10 control games that were structured the same way. 
  
 The researchers took steps to ensure participants couldn’t use clues other than direct brain communication to complete the game. Inquirers wore earplugs so they couldn’t hear the different sounds produced by the varying stimulation intensities of the “yes” and “no” responses. Since noise travels through the skull bone, the researchers also changed the stimulation intensities slightly from game to game and randomly used three different intensities each for “yes” and “no” answers to further reduce the chance that sound could provide clues. 
  
 The researchers also repositioned the coil on the inquirer’s head at the start of each game, but for the control games, added a plastic spacer undetectable to the participant that weakened the magnetic field enough to prevent the generation of phosphenes. Inquirers were not told whether they had correctly identified the items, and only the researcher on the respondent end knew whether each game was real or a control round. 
  
 “We took many steps to make sure that people were not cheating,” Stocco said. 
  
 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. 
  
 “They have to interpret something they’re seeing with their brains,” said co-author Chantel Prat , a faculty member at the Institute for Learning & Brain Sciences and a UW associate professor of psychology. “It’s not something they’ve ever seen before.” 
  
 Errors can also result from respondents not knowing the answers to questions or focusing on both answers, or by the brain signal transmission being interrupted by hardware problems. 
  
 “While the flashing lights are signals that we’re putting into the brain, those parts of the brain are doing a million other things at any given time too,” Prat said. 
  
 The study builds on the UW team’s initial experiment in 2013, when it was the first to demonstrate a direct brain-to-brain connection between humans. Other scientists have connected the brains of rats and monkeys, and transmitted brain signals from a human to a rat, using electrodes inserted into animals’ brains. In the 2013 experiment, the UW team used noninvasive technology to send a person’s brain signals over the Internet to control the hand motions of another person. 
  
 The experiment evolved out of research by co-author Rajesh Rao , a UW professor of computer science and engineering, on brain-computer interfaces that enable people to activate devices with their minds. In 2011, Rao began collaborating with Stocco and Prat to determine how to link two human brains together. 
  
 In 2014, the researchers received a $1 million grant from the W.M. Keck Foundation that allowed them to broaden their experiments to decode more complex interactions and brain processes. They are now exploring the possibility of “brain tutoring,” transferring signals directly from healthy brains to ones that are developmentally impaired or impacted by external factors such as a stroke or accident, or simply to transfer knowledge from teacher to pupil. 
  
 The team is also working on transmitting brain states — for example, sending signals from an alert person to a sleepy one, or from a focused student to one who has attention deficit hyperactivity disorder, or ADHD. 
  
 “Imagine having someone with ADHD and a neurotypical student,” Prat said. “When the non-ADHD student is paying attention, the ADHD student’s brain gets put into a state of greater attention automatically.” 
  
 Many technological advancements over the past century, from the telegraph to the Internet, were created to facilitate communication between people. The UW team’s work takes a different approach, using technology to strip away the need for such intermediaries. 
  
 “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,” Stocco said. “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,” he said. 
  
 Other co-authors are UW computer science and neurobiology undergraduate student Darby Losey , UW bioengineering doctoral student Jeneva Cronin, UW bioengineering doctoral student Joseph Wu, and Justin Abernethy , a research assistant at the UW Institute for Learning & Brain Sciences. ||||| Abstract We present, to our knowledge, the first demonstration that a non-invasive brain-to-brain interface (BBI) can be used to allow one human to guess what is on the mind of another human through an interactive question-and-answering paradigm similar to the “20 Questions” game. As in previous non-invasive BBI studies in humans, our interface uses electroencephalography (EEG) to detect specific patterns of brain activity from one participant (the “respondent”), and transcranial magnetic stimulation (TMS) to deliver functionally-relevant information to the brain of a second participant (the “inquirer”). Our results extend previous BBI research by (1) using stimulation of the visual cortex to convey visual stimuli that are privately experienced and consciously perceived by the inquirer; (2) exploiting real-time rather than off-line communication of information from one brain to another; and (3) employing an interactive task, in which the inquirer and respondent must exchange information bi-directionally to collaboratively solve the task. The results demonstrate that using the BBI, ten participants (five inquirer-respondent pairs) can successfully identify a “mystery item” using a true/false question-answering protocol similar to the “20 Questions” game, with high levels of accuracy that are significantly greater than a control condition in which participants were connected through a sham BBI. 
  
 Citation: Stocco A, Prat CS, Losey DM, Cronin JA, Wu J, Abernethy JA, et al. (2015) Playing 20 Questions with the Mind: Collaborative Problem Solving by Humans Using a Brain-to-Brain Interface. PLoS ONE 10(9): e0137303. https://doi.org/10.1371/journal.pone.0137303 Editor: Marco Iacoboni, UCLA, UNITED STATES Received: April 30, 2015; Accepted: August 16, 2015; Published: September 23, 2015 Copyright: © 2015 Stocco et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited Data Availability: Data are available from Dryad: doi:10.5061/dryad.g15k7. Funding: This research was funded by an award of the W. M. Keck Foundation (http://www.wmkeck.org/) to AS, CSP, and RPNR. Competing interests: The authors have declared that no competing interests exist. 
  
 Introduction Direct brain-to-brain interfaces (BBIs) are technologies that combine neuroimaging and neurostimulation methods to exchange information between brains directly in neural code. In BBIs, specific content is extracted from the neural signals of a “sender” brain, digitized, and re-encoded in the form of induced neural activity in a “receiver” brain. BBIs have been recently demonstrated in both animal models [1–3] and humans [4–6]. While BBIs in humans offer advantages in terms of the range of tasks that can be accomplished and the complexity of information that can be transferred [7], constraints on the invasiveness of brain stimulation technologies in humans limit the possible BBI paradigms. As a result, all of the existing human BBIs have adopted two standard, non-invasive, and relatively safe technologies; electroencephalography (EEG [8]) to record brain activity, and transcranial magnetic stimulation (TMS [9]) to modulate neural activity. Using these two technologies, Rao and colleagues [5] were able to detect the intention of moving the right hand in a sender, and induce the intended movement in the right hand of a receiver, thus allowing the pair to jointly cooperate to solve a visuo-motor task. Grau and colleagues [6], on the other hand, were able to transfer information between pairs of participants in the form of neurally modulated visual percepts, which could be decoded as words by the receiver through a pre-arranged code. While both experiments served as important proofs of concept, they were also subject to a number of limitations. For example, in Rao and colleagues’ study [5], the participant at the receiver end of the BBI received a stimulus to the motor cortex, which produced the intended motor action but was not consciously processed by the participant. In other words, the receiver did not experience the desire to move his or her hand. Therefore, while the BBI allowed two participants to collaborate to achieve a common goal, it did not take full advantage of the receiver’s capacity for processing information. In Grau and colleagues’ experiment [6], the information transmitted to the receiver through the stimulation of visual processing areas resulted in the conscious perception of “phosphenes,” which are temporary visual percepts in the form of lines or spots. The conscious experience of phosphenes was interpreted as a binary signal and used to encode simple words with a code akin to the Morse code. This approach takes full advantage of the human capacity to consciously process information, but because their BBI was not intended to achieve a common goal between the two participants, it lacked the collaborative nature of Rao and colleagues’ task [5]. Also, differently than Rao’s study, Grau and colleagues adopted an off-line delivery mode, where the same signals from a single sender participant were recorded and later broadcast to different receivers. Finally, none of the previous studies had the two participants engage in collaborative and interactive problem solving, in which the receiver can transmit information back to the sender. Such a “closed-loop” interaction could represent a significant advance for the potential applications of human BBI technologies. We report results from a new experiment that overcomes the limitations of these previous studies by increasing both the complexity of the tasks performed with a non-invasive BBI in humans, and the quantity of information transferred between two brains. In our experiment, five pairs of participants played a shortened version of the popular “20 Questions” parlor game, in which a participant can ask up to 20 yes/no questions in order to figure out what object a second participant is thinking of. We chose this paradigm because it presents several important features that test the utility of a BBI, including the fact that it is collaborative, potentially open-ended, operates in real-time, and requires conscious processing of incoming information. To better reflect their roles in the collaborative question-answering task, we refer to the BBI sender as “Respondent”, and the BBI receiver as “Inquirer.” As illustrated in Fig 1, the inquirer and the respondent (physically located about 1 mile apart) interact using a web interface in conjunction with the brain-to-brain interface. The respondent first thinks of an object belonging to a specific category (for example, an animal, e.g., “dog”); the inquirer then uses the web interface to select a question for the respondent (using a computer mouse) from a list shown on the computer screen. A non-invasive BBI (shown in red in Fig 1) decodes the answer directly from the respondent’s brain signals and conveys the answer to the inquirer through stimulation. PPT PowerPoint slide 
  
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 larger image TIFF original image Download: Fig 1. Architecture of the BBI and “20 Questions” Experiment. In the experiment, two participants (an “inquirer” and a “respondent”) played a question-answering game similar to “20 Questions.” The respondent is given an object (e.g., “dog”) that is unknown to the inquirer and that the inquirer has to guess. The inquirer asks a question about the object by selecting a question (using a mouse) from questions displayed on a screen. The question is then presented visually to the respondent through a web interface. The respondent answers “Yes” or “No” directly through their brain signals by paying attention to one of two flashing LEDs (“Yes” = 13 Hz; “No” = 12 Hz). The BBI uses EEG to decode the respondent’s answer, and a TMS apparatus to convey the answer to the inquirer by generating a visual percept through stimulation for “Yes” and the absence of a percept for “No.” In the figure, the BBI system is highlighted in red. https://doi.org/10.1371/journal.pone.0137303.g001 The BBI was designed to detect visual information from the respondent’s EEG activity (specifically, whether the respondent was attending to the “Yes”-labelled flashing LED or the “No”-labeled flashing LED), and elicit a corresponding visual percept in the inquirer through transcranial magnetic stimulation of the visual areas in the occipital cortex. A number of precautions (see below) were taken to ensure that the inquirer did not receive any information about the answer from any source other than the BBI itself. To ensure the validity of these precautions, each experimental session consisted of 10 experimental games and 10 “control” games; during the control games, the BBI sounded and felt similar to the experimental trials but it did not stimulate the occipital cortex. The order of experimental/control games was randomized prior to the beginning of the experiment. Participants were told in advance about the presence of two conditions, but were not told which condition each game belonged to. 
  
 Results and Discussion The efficacy of the proposed BBI was quantified using several measures. The most straightforward is the number of games in which the inquirer was successfully able to identify the object that the respondent was thinking of. On average, our five pairs of subjects were able to successfully guess the correct object in 72% of the games in the experimental condition using information available from the BBI, in contrast to only 18% successfully guessed during the control conditions. Because the distributions of correct guesses in both the experimental and control conditions were Normal (as assessed by the Shapiro-Wilk Normality test: W > 0.91, p > 0.48) and the two distributions had equal variances (Levene’s test: F(1, 8) = 0.07, p = 0.79), the difference between conditions was tested with a paired T-test. he difference between the experimental and control conditions was highly significant (paired t(4) = 13.50, p = 0.0002, Cohen’s d = 9.55). When examining the control condition, it is important to measure chance performance. Chance performance can be estimated in two ways, either by assuming a random inquirer who classifies the respondent’s answers as “Yes” or “No” with equal probability, or assuming an ideal inquirer who always classifies the respondent’s answers as “No” because no cortical input is received in the control condition. Because of the specific ways in which our lists and questions were constructed, both estimates yield the same chance performance of 12.5%. Statistical analysis revealed that performances of all participants were above chance in the experimental condition (single-sample t(4) = 8.97, p = 0.0008), but not in the control condition (single-sample t(4) = 0.78, p = 0.50; Fig 4A). PPT PowerPoint slide 
  
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 larger image TIFF original image Download: Fig 4. Different Measures of BBI Performance Across Conditions and Subjects. (A) Mean number of objects correctly guessed by the inquirer over 10 experimental (red) and 10 control trials (black) across 5 pairs of subjects; chance performance is 0.125 (dotted line); (B) Mean area under the ROC curves (see Fig 5, below); chance performance is 0.5 (dotted line); (C) Mean number of bits transferred during the experimental and control conditions, using the mutual information criterion; chance performance corresponds to 0 bits (dotted line). In all figures, the grey lines represent the five pairs of participants. Note that in (A), two pairs near the center of the plot had identical performance, giving the appearance of only four lines. https://doi.org/10.1371/journal.pone.0137303.g004 A more detailed way to examine our results is to analyze a BBI using signal detection theory, or equivalently, to treat the BBI as a classification problem. In this analysis, the signal (or, in classification terms, the label) is the true response to each question, and the prediction (or the class) is the inquirer’s understanding of the respondent’s answer. The performance of each pair can then be described using Receiver Operating Characteristic (ROC) analysis [18]. In ROC analysis, performance is represented as a point in the coordinate space defined by two axes representing the true positives rate and the false positives rate. In this space, an ideal classifier will occupy the upper-left corner of the plot, corresponding to 0% false positives and 100% true positives. A random classifier, by contrast, would occupy any of the positions along the upwards diagonal line, where for each proportion of true positives an equal amount of false positives occurs. For each pair in our experiments, we expect performance in the experimental condition to be near to the upper-left corner, and performance in the control condition to be near the diagonal line. Each pair’s performance can be further broken down into separate data points, one for the respondent (considering the true response as the ground truth and the output of the EEG detection as the prediction) and one for the inquirer (considering the TMS pulse as the ground truth and the inquirer’s decision as the prediction). Fig 5 plots each of these ROC points separately for each pair (Fig 5A) and for each participant within each pair (Fig 5B and 5C). PPT PowerPoint slide 
  
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 larger image TIFF original image Download: Fig 5. Performance of Each Pair of Subjects. Each plot illustrates the performance of pairs of subjects in terms of Receiver Operating Characteristic (ROC) for the experimental (red dots) and control (gray dots) games. The first plot (A) depicts the performance of each pair as whole while the other two plots represent the individual performances of respondents (B) and inquirers (C) in each pair. Overlapping points are indicated by darker shades of red or gray. https://doi.org/10.1371/journal.pone.0137303.g005 In the ROC plot, the performance associated with each point can be quantified as a single number, which represents the area of the polygon formed by connecting the point to the lower-left, lower-right, and upper-right corners of the plot, with coordinates (0, 0), (0, 1) and (1, 1), respectively [18]. This value is known as Area Under the Curve (AUC) and ranges from 1.0 (for an ideal classifier that recognizes all of the true positives without any false positives) to 0.5 (for a random classifier, where increasing the true positive rate produces an equivalent increase in the false positive rate [18]). Individual AUCs were calculated using ROCR package [19]. Since the distribution of AUC values was normally distributed (Shapiro-Wilk test, W > 0.84, p > 0.16) and had similar variance (Levene’s test, F(1, 8) = 0.05, p = 0.82) in both conditions, the data was analyzed with Student’s T-test. The mean raw AUC for the control condition was 0.54, a number that is not significantly different from that for chance (single-sample t(4) = 1.27, p = 0.27). On the other hand, the raw AUC for the experimental condition was 0.90, which is significantly larger than the AUCs for both the control condition (paired t(4) = 11.93, p = 0.0003, Cohen’s d = 8.44) and chance (single-sample t(4) = 13.43, p = 0.0001; see Fig 4B). In the ROC plot, the performance associated with each point can be quantified as a single number, which represents the area of the polygon formed by connecting the point to the lower-left, lower-right, and upper-right corners of the plot, with coordinates (0, 0), (0, 1) and (1, 1), respectively [18]. This value is known as Area Under the Curve (AUC) and ranges from 1.0 (for an ideal classifier that recognizes all of the true positives without any false positives) to 0.5 (for a random classifier, where increasing the true positive rate produces an equivalent increase in the false positive rate [18]). Individual AUCs were calculated using ROCR package [19]. Since the distribution of AUC values was normally distributed (Shapiro-Wilk test, W > 0.84, p > 0.16) and had similar variance (Levene’s test, F(1, 8) = 0.05, p = 0.82) in both conditions, the data was analyzed with Student’s T-test. The mean raw AUC for the control condition was 0.54, a number that is not significantly different from that for chance (single-sample t(4) = 1.27, p = 0.27). On the other hand, the raw AUC for the experimental condition was 0.90, which is significantly larger than the AUCs for both the control condition (paired t(4) = 11.93, p = 0.0003, Cohen’s d = 8.44) and chance (single-sample t(4) = 13.43, p = 0.0001; see Fig 4B). A final measure of interest is the number of bits that were successfully transferred between the respondent and the inquirer using the BBI. Because each answer of the respondent excludes half of the remaining options in the inquirer’s list, it theoretically conveys exactly one bit of information. Thus, information can be calculated as the sum of all the correct answers understood by the inquirer. This measure, however, might overestimate performance, as it does not account for the fact that negative answers are always correctly identified in the control conditions (that is, “0” bits are always transferred correctly), and that the distribution of the respondent’s answers might be skewed (i.e., there might be more negative answers than positive during the experimental conditions). A more conservative and precise measure is the Mutual Information (MI) between the ground-truth correct answers (considered as the input to the BBI) and the inquirer’s understanding of the received answers (the output of the BBI) [20]. MI can be calculated by first converting the set of correct answers and the inquirer’s responses into two binary vectors C and R, with every single answer c in C and r in R coded as 1 for “Yes” and “0” for “No”, and then using the following formula: MI was computed using the Infotheo package [21]. Because MI ranges between 0 and 1 and is calculated in natural logarithms, the actual number of bits transferred is calculated by first converting the MI value into the corresponding base two logarithm, and then multiplying it by the total number of answers given over the course of the experiment (in this case, 30). Because the distribution of MI values is inherently non-Normal (Shapiro-Wilk test, W = 0.78, p = 0.06), the raw data was square-root transformed before being analyzed. The transformed MI scores were more Normally distributed (Shapiro-Wilk test, W = 0.82, p = 0.12) and had comparable variances across conditions (Levene’s test, F(1,8) = 0.14, p = 0.71), thus fitting the requirements of Student’s T-test. In the experimental condition, the raw mean number of bits transferred was 16.02, which was significantly greater than the mean 1.16 bits transferred during the control condition (paired t(4) = 6.02, p = 0.004, Cohen’s d = 5.87 Fig 4C). The raw number of bits transferred in the experimental condition was also greater than chance, which, in the mutual information framework, corresponds to 0 bits (single-sample t(4) = 11.32, p = 0.0003). Contrastingly, the average of 1.16 bits transferred during the control condition was not significantly different than chance (single-sample t(4) = 1.88, p = 0.13). In summary, the different measures of BBI performance collectively demonstrate that the inquirers correctly identified the respondents’ answers during the experimental conditions, but performed at chance levels during the control games. These results have two implications. First, the success of the five pairs during the experimental condition confirms that the interactive BBI was successful and generalizable across different human subjects. Second, the fact that the pairs’ performance was at chance levels during the control condition implies that the communication between the two participants was relying specifically on the information provided by the direct brain-to-brain connection, rather than through other environmental or sensory cues. 
  
 Conclusions This paper presents the successful demonstration of a new, non-invasive BBI in humans, which allowed pairs of participants to successfully collaborate and complete a series of question-and-answer games using information transferred between their brains. This BBI paradigm significantly extends and improves previous protocols in that (1) it involves the transfer of consciously perceived information in the form of phosphenes, (2) works in real-time, and (3) permits bidirectional information exchange between two participants. In this sense, this experiment represents a significant step forward towards the goal of creating BBIs with real-world applications. Because phosphenes are private to the receiver and can be perceived under a variety of conditions, or even while performing other actions, they represent a more versatile and interesting means of transferring information than the induced finger movements used in [5]. The amount of information transferred (as measured by the number of bits) in the current experiment is also significantly greater than that transferred in previous BBI experiments, e.g., close to 25 bits for one of the pairs (see Fig 4C) compared to a maximum of 13.4 bits in [5]. Finally, another strength of the current study is the enrollment of participants in terms of number and diversity. With ten total participants, this is the largest BBI experiment to date; while the number might seem small compared to more traditional EEG BCI studies, the reported effect sizes are considerable, with Cohen’s d values ranging from 5.87 to 9.55. As a comparison, these effect sizes would correspond to Pearson correlation coefficient values between 0.96 and 0.99. With such effect sizes, calculations suggest that between 3 and 4 pairs of subjects would already be sufficient to achieve a statistical power > 0.99 for significance thresholds of p < 0.05, therefore having less than 1% chance of incurring in Type II errors. Our sample size is therefore statistically adequate to support our conclusions. In addition, this is also the most diverse BBI experiment in terms of subject characteristics. For example, to our knowledge, this is the first human BBI experiment to include female participants. Thus, our results are encouraging in terms of their ability to demonstrate the generalizability of BBIs to the general population. The current experiment is not without limitations. The most obvious of these is that, as in previous BBI demonstrations, our paradigm does not transfer information better than would be expected with canonical means, such as when two individuals communicate verbally. For instance, it is reasonable to assume that any pair of our participants would be able to correctly guess the object in 100% of the games if they were given the possibility to communicate verbally. However, in circumstances including a non-verbal participant (e.g., an individual with Broca’s aphasia), or pairs of participants that do not speak the same language, it is highly likely that the BBI paradigm would outperform a canonical verbal protocol. Note that the count of correct final guesses greatly underestimates the performances of individual participants. This is for two reasons; first, all the answers in a game need to be correct for a correct guess of the chosen object; and second, the accuracy of a pair is the product of the accuracies of its two independent participants. When the accuracies of each respondent and inquirer in identifying each response are considered, the results are indeed impressive (93.5% and 94.0% accuracies, respectively), with two participants achieving a perfect score (Respondents 2 and 3, in the Experimental condition). These performances correspond to a decline of only about 6% from the levels assessed at the end of the training phase for the inquirers. This small decline can be explained by mental fatigue, which was likely induced by the length of the experimental sessions (approximately 2 hours for the respondents, and 2.5 hours for the inquirers) and the need for participants to fixate the screen for long periods of time. There is, in fact, experimental evidence suggesting that reduced attention has detrimental effects on both SSVEP detection [22] and phosphene perception [23]. A second limitation of our study is that, while the experimental paradigm as a whole allowed bi-directional transfer of information between the respondent and the inquirer, the BBI remained unidirectional, allowing only the transfer of information from the respondent to the inquirer. Fully bi-directional BBIs, if executed in real-time, require the integration of EEG and TMS technologies for each participant, and the development of tasks in which all of the relevant information can be transmitted solely using the BBI. A final limitation is that the code used herein to transmit information was relatively simple, essentially relying on the transmission of binary perceptual signals. None of these limitations is inherent to the technologies or paradigms we adopted for the BBI. For example, EEG and TMS [24], or alternately fMRI and TMS [25], can be used concurrently, thus enabling true bidirectional BBIs. We intend to investigate such BBIs in the future. Our current efforts are aimed at increasing the complexity of information transmitted through human BBIs, such as the transmission of affective states and other types of information that would be otherwise difficult to verbalize. Under these circumstances, larger amounts of information could potentially be transferred, and a BBI would confer a distinct advantage over canonical, symbolic means of communication. We see this as an exciting venue for future research. 
  
 Acknowledgments The authors would like to thank Devapratim Sarma for his help in designing the real-time EEG data processing interface. 
  
 Author Contributions Conceived and designed the experiments: AS CSP DML JAA JAC RPNR. Performed the experiments: AS DML JAA JAC. Analyzed the data: AS DML JAC. Contributed reagents/materials/analysis tools: AS CSP RPNR. Wrote the paper: AS CSP DML JAC RPNR. Designed and implemented the experimental software: JW. |||||
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assistant: University of Washington scientists say they pulled off the amazing feat of linking two minds over the Internet—and they didn't have to stick electrodes into anybody's brain to do it. Instead, pairs of study participants a mile apart wore caps—one connected to an EEG machine monitoring brain activity, the other connected to a magnetic coil capable of stimulating the visual cortex—to play a game of "20 Questions," the Seattle Times reports. The researchers, whose study is published in the journal PLoS One, say that when the player with the coil used selected questions about an object from a list using a mouse, the player with the EEG cap was able to communicate a "yes" or "no" by focusing on a light, causing the other player to see a flash of light when the answer was "yes." The researchers say the subjects determined the correct object in 72% of the "mind meld" games and in just 18% of control rounds. "This is the most complex brain-to-brain experiment, I think, that's been done to date in humans," the lead researcher says in a university press release. "It uses conscious experiences through signals that are experienced visually, and it requires two people to collaborate." The researchers say the project could be a gigantic breakthrough for communications, and they're working on ways to transmit brain states, which could transform a weary or distracted brain into an alert one. (Another study found that climbing a tree is great for your brain, even if you're in your 50s.)