Mind-Reading Machines
Mind-Reading Machines
| fMRI scanners measure bloodflow in the brain, highlighting areas of increased activity. They could potentially be used to read our minds in the future © Alamy |
2-10 YEARS AWAY – Knowing what somebody is thinking would be a boon to law enforcement, suspicious partners, or Facebook advertisers. But attempts to match brain activity to specific thoughts have been crude and limited. But Prof Marcel Just, a psychologist at Carnegie Mellon University, has used functional magnetic resonance imaging (fMRI) to scan the brain and identify ideas as they form. His work goes beyond what a word looks or sounds like, to the building blocks of meaning.
fMRI is not usually time-specific. If someone’s brain is being scanned as they form a sentence, the successive ideas in the sentence will be blurred together in the scan image. “The novelty is our ability to separate out the individual concepts of the sentence,” says Just. This means training software to recognise the patterns of brain activity associated with different sentence elements.
In Just’s study, participants lay inside fMRI scanners and read sentences such as ‘The angry lawyer left the office’, designed to include broad concepts like emotion and changes of location. Data from these scans was used to build models of how sentences with similar meanings, such as ‘The tired jury left the court’, would be represented in brain activity. These predictions were consistent between individuals, suggesting that our brains handle these concepts in a similar way.
“We all use the same set of elements, even people who speak different languages,” says Just. “A model trained on data from English speakers can recognise thoughts from Mandarin speakers.”
There are limitations. While broad meanings can be reconstructed from the scans, similar concepts like tea/coffee, fish/duck may be harder to distinguish. Also, the subject has to be completely cooperative, which means it wouldn’t work well as an interrogation technique. And for now it requires an unwieldy and expensive fMRI scanner.
But Just’s team are working on an EEG (electroencephalography) version, which would only need a simple electrode cap to record electrical signals in different parts of the brain. He is optimistic about how soon a workable mind-reading device could be available. “Our grant ends in two years,” he says. “Ten years would be very slow and disappointing.”
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