Static MRI scans of a human brain in cross-section
Credit: iStockphoto
BERLIN: In a remarkable world first, brain scans have been used to successfully read peoples' minds.
Previously, scientists had been able to detect decisions about making physical movements before those movements appeared. But now researchers at Berlin's Bernstein Center for Computational Neuroscience claim they are the first to decipher in advance decisions people made about what future high-level mental activity to engage in - in this case, whether to add or subtract two numbers.
While still in its initial stages, the techniques may eventually have wide-ranging implications for everything from criminal interrogations to airline security checks. And that alarms some ethicists, who fear the technology could one day be abused by authorities, marketers, or employers.
MRI scanners detect brain activity by measuring tiny differences in blood flow - the brain directs more blood to different parts as they are required.
Researchers have long used these machines to identify different types of brain activity and scientists in the United States have recently developed brain scans designed for lie detection.
But outside experts say the work led by neuroscientist John-Dylan Haynes at the Bernstein Centre is groundbreaking.
"The fact that we can determine what intention a person is holding in their mind pushes the level of our understanding of subjective thought to a whole new level," said psychiatrist Paul Wolpe at the University of Pennsylvania in Philadelphia, who was not connected to the study.
The research, which began in July 2005, has been of limited scope: only 21 people have been tested so far. And the team's 71 per cent accuracy rate is only about 20 per cent more successful than woud be expected by random chance.
Still, the research - which is also ongoing at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany, where Haynes has another lab - has been generating strong interest in the scientific community.
"Haynes' experiment strikes at the heart of how good we will get at predicting behaviors," commented Todd Braver, a psychologist at Washington University, in St. Louis, Missouri. "The barriers that we assumed existed in reading our minds keep getting breached."
In the study, participants were told to decide whether to add or subtract two numbers a few seconds before the numbers were flashed on a screen. In the interim, a computer captured images of their brain waves to predict the subject's decision - with one pattern suggesting addition, and another subtraction.
Haynes' team began its research by trying to identify which part of the mind was storing intentions. They narrowe in on the prefrontal cortex region by scanning the brain to look for bursts of activity when subjects were given choices.
Then they went about studying which type of patterns were associated with different intentions.
"If you knew which thought signatures to look for, you could theoretically predict in more detail what people were going to do in the future," said Haynes.
For the moment, reading minds is a cumbersome process and there is no chance scientists could spy on decision-making surreptitiously. Haynes' studies focus on people who choose between just two alternatives, not the infinite number present in everyday life.
But scientists are making enough progress to make ethicists nervous, since the research has already progressed from identifying the regions of the brain where certain thoughts occur to identifying the very content of those thoughts.
"These technologies, for the first time, give us a real possibility of going straight to the source to see what somebody is thinking or feeling, without them having any ability to stop us," said Hank Greely, director of Stanford University's Center for Law and the Biosciences in California.
"The concept of keeping your thoughts private could be profoundly altered in the future," he said.
Some civil libertarians have envisaged a future in which authorities could take action against individuals before they commit a crime - a scenario explored in the 2002 science fiction film Minority Report.
"We need to start thinking about how far we are going to allow these technologies to be used," said Wolpe.
Despite the fears, the research may have more benign practical applications. For example, Haynes says it will eventually contribute to the development of machines already in existence that respond to brain signals and allow the paralysed to change TV channels, surf the Internet, and operate small robotic devices.
More information:
John-Dylan Haynes, Bernstein Centre for Computational Science
John-Dylan Haynes, Max Planck Institute for Human Cognitive and Brain Sciences
