"Michael vectors the hidden camera to a wealthy-looking patron on his first course. A click on the joystick and the second screen lights up: this is the one that reads the client’s mind.
Mr. Rich-Guy seems happy enough according to the emotion-bar at the bottom of the display. It’s showing a lush, reassuring yellow with shades of soft green and pink. The main part of the monitor is interpreting the subject’s visual cortex: on the screen his mind’s eye view of the meal wobbles and occasionally morphs into something similar – the machine isn’t quite perfect. The prawn cocktail segues into a view of a tropical bay, a very long way from this rain-swept New York evening. The swirling yellows and greens show that this too is a pleasant association – the meal is still going well.
Michael wonders endlessly where his boss got all this stuff. As the lowest of the low in the restaurant hierarchy, he would never dream of asking though. From idle chat in the kitchen he’s discovered that the owner used to be in Military Intelligence. Somehow, some top-secret interrogation equipment managed to end up in his new venture. Behind the walls and above the false ceiling there are sensitive field detectors which can amplify the faintest swirls of an active brain."
Continue reading at sciencefiction.com.
It would be very difficult to detect brain activity at a distance - I think current experiments require the subject to be inside a scanner. I have no idea whether the signal strength is sufficient for cortical activity to be reconstructed even in principle from detectors behind a wall.