DeepMind publishes the Atari DQN paper in Nature. A single neural network learns to play 49 classic Atari games at or above human level from pixels alone.

Apple launches the Apple Watch, bringing continuous heart-rate monitoring + machine learning for health inference to tens of millions of wrists.

Google Brain develops its internal DistBelief successor, which would be released later in the year as TensorFlow. The open-source release would define ML frameworks for years.