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SHALLOW LEARNING

SETH LLOYD

Professor of quantum mechanical engineering, MIT; author, Programming the Universe

Pity the poor folks at the National Security Agency: They’re spying on everyone (quelle surprise!) and everyone is annoyed at them. But at least the NSA is spying on us to protect us from terrorists. Right now, even as you read this, somewhere in the world a pop-up window has appeared on a computer screen. It says, “You just bought two tons of nitrogen-based fertilizer. People who bought two tons of nitrogen-based fertilizer liked these detonators . . .” Amazon, Facebook, Google, and Microsoft are spying on everyone too. But since the spying these e-giants do empowers us—terrorists included—that’s supposedly OK.

E-spies aren’t people: They’re machines. (Human spies might not blithely recommend the most reliable detonator.) Somehow, the artificial nature of the intelligences parsing our e-mail makes e-spying seem more sanitary. If the only reason that e-spies are mining our personal data is to sell us more junk, we may survive the loss of privacy. Nonetheless, a very large amount of computational effort is going into machines thinking about what we’re up to. The total computer power that such data-aggregating companies bring to bear on our bits of information is about an exaflop—a billion billion operations per second. Equivalently, e-spies apply one smartphone’s worth of computational power to each human on Earth.

An exaflop is also the combined computing power of the world’s 500 most powerful supercomputers. Much of the world’s computing power is devoted to beneficial tasks, such as predicting the weather or simulating the human brain. Quite a lot of machine cycles also go into predicting the stock market, breaking codes, and designing nuclear weapons. Still, a large fraction of what machines are doing is simply collecting our personal information, mulling it over, and suggesting what to buy.

Just what are these machines doing when they think about what we’re thinking? They’re making connections between the large amounts of personal data we’ve given them and identifying patterns. Some of those patterns are complex, but most are fairly simple. Great effort goes into parsing our speech and deciphering our handwriting. The current fad in thinking machines goes by the name of deep learning. When I first heard of deep learning, I was excited by the idea that machines were finally going to reveal to us deep aspects of existence—truth, beauty, and love. I was rapidly disabused. The deep in deep learning refers to the architecture of the machines doing the learning: They consist of many layers of interlocking logical elements, analogous to the “deep” layers of interlocking neurons in the brain. It turns out that telling a scrawled 7 from a scrawled 5 is a tough task. Back in the 1980s, the first neural-network-based computers balked at this job. At the time, researchers in the field of neural computing told us that if only they had much larger computers and much larger training sets consisting of millions of scrawled digits instead of thousands, then artificial intelligences could turn the trick. Now it is so. Deep learning is informationally broad—it analyzes vast amounts of data—but conceptually shallow. Computers can now tell us what our own neural networks knew all along. But if a supercomputer can direct a handwritten envelope to the right postal code, I say more power to it.

Back in the 1950s, the founders of the field of artificial intelligence predicted confidently that robotic maids would soon be tidying our rooms. It would turn out to be easier to program a computer to beat the world chess champion than to construct a robot that could randomly vacuum a room and beep plaintively when it got stuck under the couch. Now we’re told that an exascale supercomputer will be able to solve the mysteries of the human brain. More likely, it will just develop a splitting headache and ask for a cup of coffee. In the meanwhile, we’ve acquired a new friend whose advice exhibits an uncanny knowledge of our most intimate secrets.

 
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