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Thought Crimes

Thought Crimes

Will your own brain betray you?

Imagine this: You get scooped up by police, fitted with electronic headgear, and shown a series of random pictures. Among the random pictures is a not-so-random one: A crime scene. A tiny electric twinge on your scalp tips off police; the crime scene is familiar to you. You are under arrest.

This story is made up—but the technology is not.

Decades ago, researchers discovered a neural phenomenon known as the P300 wave, a voltage spike that occurs in your brain whenever you see something familiar to you. Detectable by EEG, P300 is the basis of a lie-detection technique known as brain fingerprinting. Brain fingerprinting evidence has been deemed admissible in several court cases.

Newer techniques promise to go even further in getting inside your head.

At the 2015 AAAS Annual Meeting last weekend in San Jose, brain researcher Jack Gallant of UC Berkeley presented surprisingly faithful reconstructions of brain activity using fMRI scans, a technique called brain decoding. He also cautioned that there was, as yet, no way to distinguish between real and distorted or fabricated memories. “We have a long way to go before this stuff is reliable.”

Still, rapid strides in neuroscience raise new questions about just how far the justice system can or should go in peeking into peoples’ minds. At what point, if any, do you lose your right the privacy of your own thoughts?

Legal scholar Nita Farahany of Duke University is already on the case. She sees two potential bulwarks against neural prying: the 4th and 5th constitutional amendments, which protect against unlawful search and self-incrimination, respectively.

But even these redoubtable legal barriers may not be enough to guard against an Orwellian future in which your own brain betrays you in a court of law. Farahany cites fingerprint and DNA evidence, both routinely collected, as examples in which the body “testifies” against itself.

As scanning technologies improve, the open question of whether scrutiny of grey matter constitutes a reasonable search will become an increasingly grey area. For now, at least, your thoughts are your own.