I’ll be worried when they get this to reliably work at a distance. Imagine flashing a sign that says, “Did you commit a crime?” then being scanned by a device that detects you subconscious answer before cops swoop in to grab you for the wrong answer. Or worse, “Are you going to commit a crime today?” Precrime, indeed.

India’s use of brain scans in courts dismays critics

The new technology is, to its critics, Orwellian. Others view it as a silver bullet against terrorism that could render waterboarding and other harsh interrogation methods obsolete. Some scientists predict the end of lying as we know it.

Now, well before any consensus on the technology’s readiness, India has become the first country to convict someone of a crime relying on evidence from this controversial machine: a brain scanner that produces images of the human mind in action and is said to reveal signs that a suspect remembers details of the crime in question.

For years, scientists have peered into the brain and sought to identify deception. They have shot infrared beams through liars’ heads, placed them in giant magnetic resonance imaging machines and used scanners to track their eyeballs. Since the Sept. 11 attacks, the United States has plowed money into brain-based lie detection in the hope of producing more fruitful counterterrorism investigations.

The technologies, generally regarded as promising but unproved, have yet to be widely accepted as evidence — except in India, where in recent years judges have begun to admit brain scans. But it was only in June, in a murder case in Pune, in Maharashtra State, that a judge explicitly cited a scan as proof that the suspect’s brain held “experiential knowledge” about the crime that only the killer could possess, sentencing her to life in prison.