If I were to approach you brandishing a cattle prod, you might at first be amused. But, if I continued my advance with a fixed maniacal grin, you would probably retreat in shock, bewilderment and anger. As electrode meets flesh, I would expect a violent recoil plus expletives.

Given a particular input, one can often predict how a person will respond. That is not the case for the most intelligent machines in our midst. The creators of AlphaGo — a computer program built by Google’s DeepMind that decisively beat the world’s finest human player of the board game Go — admitted they could not have divined its winning moves. This unpredictability, also seen in the Facebook chatbots that were shut down after developing their own language, has stirred disquiet in the field of artificial intelligence.

As we head into the age of autonomous systems, when we abdicate more decision-making to AI, technologists are urging deeper understanding of the mysterious zone between input and output. At a conference held at Surrey University last month, a team of coders from Bath University presented a paper revealing how even “designers have difficulty decoding the behaviour of their own robots simply by observing them”.