"Hassabis founded DeepMind with fellow AI specialist Shane Legg and serial entrepreneur Mustafa Suleyman. The company hired leading researchers in machine learning and attracted noteworthy investors, including Peter Thiel’s firm Founders Fund and Tesla and SpaceX founder Elon Musk. But DeepMind kept a low profile until December 2013, when it staged a kind of debutante moment at a leading research conference on machine learning.
At Harrah’s Casino on the shores of Lake Tahoe, DeepMind researchers showed off software that had learned to play three classic Atari games - Pong, Breakout and Enduro - better than an expert human. The software wasn’t programmed with any information on how to play; it was equipped only with access to the controls and the display, knowledge of the score, and an instinct to make that score as high as possible. The program became an expert gamer through trial and error.
No one had ever demonstrated software that could learn to master such a complex task from scratch. DeepMind had made use of a newly fashionable machine learning technique called deep learning, which involves processing data through networks of crudely simulated neurons (see “10 Breakthrough Technologies 2013: Deep Learning”). But it had combined deep learning with other tricks to make something with an unexpected level of intelligence.
“People were a bit shocked because they didn’t expect that we would be able to do that at this stage of the technology,” says Stuart Russell, a professor and artificial intelligence specialist at University of California, Berkeley. “I think it gave a lot of people pause.”
DeepMind had combined deep learning with a technique called reinforcement learning, which is inspired by the work of animal psychologists such as B.F. Skinner. This led to software that learns by taking actions and receiving feedback on their effects, as humans or animals often do.
Artificial intelligence researchers have been tinkering with reinforcement learning for decades. But until DeepMind’s Atari demo, no one had built a system capable of learning anything nearly as complex as how to play a computer game, says Hassabis. One reason it was possible was a trick borrowed from his favorite area of the brain. Part of the Atari-playing software’s learning process involved replaying its past experiences over and over to try and extract the most accurate hints on what it should do in the future. “That’s something that we know the brain does,” says Hassabis. “When you go to sleep your hippocampus replays the memory of the day back to your cortex.”
A year later, Russell and other researchers are still puzzling over exactly how that trick, and others used by DeepMind, led to such remarkable results, and what else they might be used for. Google didn’t take long to recognize the importance of the effort, announcing a month after the Tahoe demonstration that it had acquired DeepMind."
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