Here's how it's going to go:
- Somebody in some lab will develop a brain sensor technology that doesn't quite need major surgery to install and picks up one or two orders of magnitude more data points.
- The paper will titled A new non-intrusive measurement system for synaptic potentials or something like that. The press release: A revolution in neural interfaces. The viral media headlines: Scientists build the real-world Matrix brain plug.
- The scientists will spin-off an startup to develop systems for medical research and prosthetics.
- One of the Usual Suspects will invest on it at a pre-money valuation of the GDP of a nontrivial chunk of South Korea.
- About two months later they will grab 40 temp workers/volunteers, put an early version of the device in them, and record a comparative handful of synaptic potentials under a couple of very specific situations the paper will over-generalize as Lying and Telling the truth.
- Then they will run those raw numbers through the dumbest most complex large-scale neural network classifier you could imagine.
- Neuroscientists will squint at the "model" and mumble something about "the topology of the connectome" or whatever.
- The viral headlines will be (THE USUAL SUSPECT) BUILDS A BRAIN-READING LIE DETECTOR.
- Business people will talk about how large the chunk of South Korea will have to be to match the valuation of the next round. Non-business people will talk about the ethics of perfect mind reading. Tech people will talk about the Borg. Neuroscientists will make clear and convincing explanations about how this is *not* a lie detector, will get a thousandth of the visibility of the guy founding a fake telepathic porn company, and give up.
- The company will start building overpriced devices that don't even use the same technology but do "brain stuff."
- Every one of the many security forces questionable enough to still pretend to believe in polygraphs will buy and start using them with the same standards of fairness, scientific accuracy, and respect for the truth.
- A lot of people with faces suspicious enough to get the "brain polygraph" test will be flagged by the system, judges will not understand or don't care it's nonsense, and juries will believe the reputation of (the usual suspect) over whatever neuroscientist the accused happens to know.
- People will still be discussing the ethics of perfect mind reading.
- A few years later there will be a case of an error so egregious that somebody in the US Congress will make some noise about the illegality of those devices. That will go nowhere.
- Unrelatedly, the device will be in regular or pretended use in prisons, public schools, temp- and low-wage job roles, and private military research companies.
- About five or ten years later, maybe, somebody will publish a breakthrough paper on brain functionality based on the fifth-generation descendant of the original sensor the company isn't using on its devices because it's not cheap enough. This will have absolutely no visibility or impact outside science, philosophy, and medicine.
None