What is deep learning? And how is it different from AI?

Deep learning, a technology based on artificial neural networks, has revolutionised artificial intelligence in the space of a few years. But what exactly is it? Used by Siri, Cortana and Google Now to understand speech and recognise faces, deep learning is often confused with the concept of artificial intelligence (AI), so much so that the two terms are thought to be synonymous. Deep learning is a branch of machine learning, which in turn is a subset of AI. Born with the development of computers, research in AI was quickly characterised by the emergence of different currents. One of them sought inspiration from the workings of the human brain in an attempt to create artificial neural networks.