Scientists Getting Better at Mind-Reading

Aug. 16, 2006 — Scientists have gone beyond mind-reading by predicting recollections of certain people, places and things even before the thinkers are aware of the ponderings themselves, according to a new overview of recent advancements in scientific mind-reading.

The paper, which will be published in a forthcoming issue of Trends in Cognitive Sciences, claims many recent breakthroughs are due to a process called multi-voxel pattern analysis (MVPA). Researchers analyze our minds virtually by dividing brains into tiny, 3-D cubes called voxels.

Standard mind-reading methods attempt to decipher the output of individual "cubes," but the newer technique focuses on a bigger picture.

"MVPA is asking a different question," said Kenneth Norman, lead author of the paper. "Instead of asking, ‘What does this little piece of brain do?’ MVPA looks at lots of voxels at once and asks, ‘What information is represented in the pattern of activity distributed across the brain?’"

Norman, an assistant professor of psychology at Princeton University, explained to Discovery News that pattern classification and data mining techniques used for handwriting recognition are now being applied to functional magnetic resonance imaging of the brain.

For example, a researcher may ask someone to think about certain faces, locations and objects. The researcher then records the brain patterns associated with each thought. When subjects are asked to repeat the exercise, computer software can match the prerecorded brain patterns to the current ones, which may tell the classifier what the person is thinking.

Researchers can also see certain thoughts developing, even before they become full-blown, conscious ideas. Around 5.4 seconds before a person recalls something seen, heard, or experienced earlier in the study, category-specific patterns of brain activity start to emerge, which help investigators predict what the person is going to remember.

"A really important point is that the classifier can only ‘read out’ cognitive states that it has been trained to recognize," Norman said. "If you train up the classifier to recognize shoes, bottles and chairs, it won’t be able to say when you’re thinking about scissors."

Nevertheless, the technique has led to some amazing feats of mind-reading.

A recent competition at the University of Pittsburgh asked various scientific teams to read the minds of people who watched episodes of the television comedy show "Home Improvement." After gathering brain data during the first two episodes, many researchers were able to predict test subject ratings for things like humor, music, characters and onscreen faces while the subjects watched the third episode. Norman’s team was one of the winners.

In other studies, scientists successfully figured out when people are looking at pictures or sentences as well as when they are viewing ambiguous or non-ambiguous sentences. Researchers have also predicted when a person is lying about the identity of a playing card.

"MVPA analyses hold out the promise of our being able to non-invasively track the flow of information in the human brain and see how it is transformed at different stages of neural processing," said Norman.

Norman points out this ability could be used in the medical field. He explains once scientists can characterize information processing in normal populations, they should be able to recognize differences among those with memory problems or other cognitive disorders, including schizophrenia.

Frank Tong, assistant professor of psychology at Vanderbilt University, also conducts research analyzing multi-voxel patterns to read out what people are seeing or perceiving. He says he "strongly agrees" with "the view of the promising nature of this emerging field."

While both Norman and Tong envision a fruitful future for mind-reading studies, Norman points out there are limits to how far the research can — and should — advance.

"We are still a very long way off from the kind of mind reading that you see on sci-fi shows where you can read arbitrary thoughts without the person’s knowledge or consent," he said.