In this contributed article, Pippa Cole, Science Writer at the London Institute for Mathematical Sciences, discusses new research on artificial neural networks that has added to concerns that we don’t have a clue what machine learning algorithms are up to under the hood. She highlights a new study that focuses on two completely different deep-layered machines, and found that in fact they did exactly the same thing, which was a huge surprise. It’s a demonstration of how little we understand about the inner workings of deep-layered neural networks.