For centuries, mentalists astounded crowds by seeming to plumb the depth of their souls—effortlessly unearthing audience members’ memories, desires, and thoughts. Now, there’s concern that neuroscientists might be doing the same by developing technologies capable of “decoding” our thoughts and laying bare the hidden contents of our mind. Though neural decoding has been in development for decades, it broke into popular culture earlier this year, thanks to a slew of high-profile papers. In one, researchers used data from implanted electrodes to reconstruct the Pink Floyd song participants were listening to. In another paper, published in Nature, scientists combined brain scans with AI-powered language generators (like those undergirding ChatGPT and similar tools) to translate brain activity into coherent, continuous sentences. This method didn’t require invasive surgery, and yet it was able to reconstruct the meaning of a story from purely imagined, rather than spoken or heard, speech.
Dramatic headlines have boldly, and prematurely, announced that “mind-reading technology has arrived.” These methodologies currently require participants to spend an inordinate amount of time in fMRIs so the decoders can be trained on their specific brain data. The Nature study had research subjects spend up to 16 hours in the machine listening to stories, and even after that the subjects were able to misdirect the decoder if they wanted to. As Jerry Tang, one of the lead researchers, phrased it, at this stage these technologies aren’t all-powerful mind readers capable of deciphering our latent beliefs as much as they are “a dictionary between patterns of brain activity and descriptions of mental content.” Without a willing and active participant supplying brain activity, that dictionary is of little use.
Still, critics claim that we might lose the “last frontier of privacy” if we allow these technologies to progress without thoughtful oversight. Even if you don’t subscribe to this flavor of techno-dystopian pessimism, general skepticism is rarely a bad idea. The “father of public relations,” Edward L. Bernays, was not only Freud’s nephew, he actively employed psychoanalysis in his approach to advertising. Today, a range of companies hire cognitive scientists to help “optimize” product experiences and hack your attention. History assures us that as soon as the financial calculus works out, businesses looking to make a few bucks will happily incorporate these tools into their operations.
A singular focus on privacy, however, has led us to misunderstand the full implications of these tools. Discourse has positioned this emergent class of technologies as invasive mind readers at worst and neutral translation mechanisms at best. But this picture ignores the truly porous and enmeshed nature of the human mind. We won’t appreciate the full scope of this tool’s capabilities and risks until we learn to reframe it as a part of our cognitive apparatus.
For most of history, the mind has been conceptualized as a sort of internal, private book or database—a self-contained domain that resides somewhere within ourselves, populated by fixed thoughts that only we have direct intimate access to. Once we posit the mind as a privately accessible diary containing clearly defined thoughts (or “internalism,” as it’s sometimes called) it’s not much of a jump to begin asking how we might open this diary to the external world—how someone on the outside might decipher the hidden language of the mind to pierce this inner sanctum. Theologians thought that this access would come from the divine through a God capable of reading our deepest thoughts. Freud thought that a trained psychoanalyst could make out the true contents of the mind through hermeneutical methods like dream interpretation. Descartes, ever a man of the Enlightenment, had a more physicalist hypothesis. He argued that our souls and minds are closely attached to the pineal gland and expressed its will. In doing so, he opened us up to the idea that if we could establish the right correspondence between thought and bodily motion, we might be able to work backward to mental content itself.
More contemporary approaches have followed in these footsteps. Polygraphs, or lie detectors, attempt to use physiological changes to read the content of our beliefs. Tang’s own statements on the thought decoder as a “dictionary” between brain scans and mental content expresses the modern version of this notion that we might decipher the mind through the neural body. Even critics of thought decoding, with their concerns about privacy, take this internalist theory of mind for granted. It’s precisely because of the supposedly sheltered nature of our thoughts that the threat of outside access is so profoundly disturbing.