Our Not-So-Secret Thoughts


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Our intimacy starts where no one else can hear or see it. Our thoughts, the dialogues we have with ourselves, are probably the last bastion against external intrusion. Could it be possible, one day, to breech this fortress and listen in to what we are thinking? In 2010, two scientists at the US Harvard University reported that we spend almost half of our days daydreaming. Even if we tend to focus our thoughts on our problems, as stated in their article “A Wandering Mind is an Unhappy Mind”, at least we can be certain that they belong to us. Given the rapid development of certain technologies, we may perhaps not be able to hide behind this conviction for much longer.


Last April, Facebook announced its intention to read the content of our thoughts so that we can share them immediately with the rest of the world, without needing to dictate a message or type it on a keyboard. As well as the ethical questions raised by such a project, is this technically feasible today? Functional magnetic resonance imaging (fMRI) is the technique that can access brain activity the most accurately. It detects the quantity of oxygen consumed in a given region of the brain, and hence its degree of activation. In 2012, two American teams at Princeton University and Dartmouth College gave an MRI to subjects as they watched Steven Spielberg’s film Raiders of the Lost Ark. They thus managed to build a cerebral map of “semantic” categories (animals, faces, etc.). By presenting the same subjects with new images sometime later, they managed to decode the semantic category to which the images observed belonged using brain signals, in 65% of cases, exceeding the contingency of random statistics. Despite the prowess of this study, the signals in question remain “raw”, as they result from the activity of too many neurons to be finely decoded. Also, these machines weigh several tonnes and cannot be used as Mark Zuckerberg would probably imagine.


Reading someone’s mind will likely require interacting directly with the neurons and thus getting into the heart of our nervous system. One case is currently astounding the scientific community on this issue. Krista and Tatiana Hogan, Canadian Siamese twins, have their skulls and their brains anatomically connected. Although doctors only gave them a few days to live, these 11-year-old preteens are lively and happy today. As soon as they were born, their mother noticed a surprising thing: when one was given a pacifier, the other stopped crying. Later, she discovered that when showing a doll to Krista, Tatiana with her eyes hidden said, “My sister can see a doll.” Thus, by an improbably exchange of nerve connections, these sisters are able to access teach other’s mental life, while retaining their own individuality and personality.


Elon Musk, another “guru” from Silicon Valley, understands this well. In a push to control a computer by thought, he has just launched Neuralink, a new company that is not hiding its ambition to develop interfaces to make direct contact with neurons, not by opening the skull, but maybe (who knows?) via blood vessels. For some a dystopia, for others a biomedical revolution or an inevitable future, it is far from certain that this research will succeed any time soon. We can be sure that initial developments will focus on enhancing the lives of millions of people suffering from mental or motor disabilities. Our responsibility as scientists is to inform so that fair ethical choices can be made when the question is raised.





Adrien Peyrache


Adrien Peyrache heads at McGill University in Canada a research laboratory devoted to studying the neuronal processes involved in spatial navigation and memory.

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November 11, 2018

November 11, 2018

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