The race to the top among the world's leaders in artificial intelligence

A spectrogram of the sound of a human voice, used by voice-recognition software. The idea of artificial intelligence (AI) -- systems so advanced they can mimic or outperform human cognition -- first came to prominence in 1950, when British computer scientist Alan Turing proposed an'imitation game' to assess whether a computer could fool humans into thinking they were communicating with another human. Soon after, researchers at Princeton University in New Jersey built MADALINE, the first artificial neural network applied to a real-world problem. Their system, modelled on the brain and nervous system, learnt to solve a maze through trial-and-error. Since then, the rise of AI has been enabled by exponentially faster and more powerful computers and large, complex data sets.