Neurotechnology: how does new mind-reading technology work?

Sci-fi stories about mind-reading machines apear to be on the verge of becoming a reality following a major new advance by neuroscientists.

According to a study published in Nature journal, researchers at the University of Texas at Austin have developed an AI-based decoder that can translate brain activity into speech. The development is the latest in a series of advances in neurotechnology that are ushering in “a brave new world”, said NPR.

But while the research “could have all sorts of health applications”, some experts argue that the loss of mental privacy is a “slippery slope”.

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How does the technology work?

A “non-invasive brain-computer interface” does the heavy lifting in the Texas team’s system, which is a “marriage of two technologies”, reported Vox Future Forward’s Sigal Samuel.

For the study, the scientists used fMRI scans to track changes in blood flow to different areas in the brains of three participants while listening to storytelling podcasts. Using AI language models “similar to the now infamous ChatGPT”, said Samuel, the team were able to use the scan data “to associate a phrase with how each person’s brain looks when it hears that specific phrase”.

The decoder reconstructed speech with “uncanny accuracy” while the participants listened to the stories, said The Guardian’s science correspondent Hannah Devlin, and even when they “silently imagined one” .

And while previous language decoding systems have “required surgical implants”, the Texas trio were only required to lie in a scanner for the AI technology to learn the patterns of their brain activity.

“For a non-invasive method, this is a real leap forward compared to what’s been done before, which is typically single words or short sentences,” said Dr Alexander Huth, who led the research.

What are the potential risks?

Some experts fear that the technology poses a threat to mental privacy.

“I’m not calling for panic, but I think it’s a big wake-up call for policymakers and the public,” bioethicist Gabriel Lazaro-Munoz of Harvard Medical School told Nature journal.

Lazaro-Munoz and other critics point to issues such as consent, and what delving deeper into peoples’ thoughts might mean.

David Rodriguez-Arias Vailhen, a bioethics professor at Granada University, raised concerns about a future where such tech could be used against people’s will and possibly without their knowledge.

“Our mind has so far been the guardian of our privacy,” he told The Telegraph. “This discovery could be a first step towards compromising that freedom in the future.”

The Financial Times’s science journalist Anjana Ahuja warned back in 2019 of the risks if such technology were “in the hands of the unscrupulous”. It might be used by “advertisers to gauge consumer delight and disgust”, or by employers to “measure compliance and dissent”, she suggested.

Such interference could ultimately create a “peephole for voyeurs”, she added.

What are the benefits?

The new technology “might eventually help individuals with brain injuries or paralysis regain the ability to communicate”, said Science Magazine.

Nita Farahany, a bioethicist at Duke University, told the magazine that while further major advances were needed, the tech might one day be “really transformational for people who need the ability to be able to communicate again”, such as those with locked-in syndrome or who have suffered a stroke.

According to New Scientist, another potential use of such computational modelling could be “investigating mental health conditions”, which could help with diagnosis.

A mind-reading brain implant has already been used to help a paralysed man regain the ability to walk. Gert-Jan Oskam, from the Netherlands, suffered a paralysing spinal cord injury in a motorcycle accident more than a decade ago.

But thanks to small implants which have “rehabilitated the connection between his legs and his mind”, said Business Insider’s health correspondent Hilary Brueck, he can now walk “just over 300 feet – all on his own”.

So how close are we to mind reading?

Although “the technology to decode our thoughts is drawing ever closer”, said neuroscientist Christina Maher, “we don’t need to worry just yet”.

In experiments by the Texas team, a decoder “trained on one person’s thoughts performed poorly when predicting the semantic detail from another participant’s data”, wrote Maher, of the University of Sydney, in an article on The Conversation. Plus, “participants could disrupt the decoding by diverting their attention to a different task such as naming animals or telling a different story”.

Movement in the fMRI scanner was also found to “disrupt the decoder”. And the “decoder does not currently work on data other than fMRI, which is an expensive and often impractical procedure”, added Maher.

“Considering these requirements, and the need for high-powered computational resources, it is highly unlikely that someone’s thoughts could be decoded against their will at this stage,” she concluded.