 In the 2010s, a class of computational models known as deep neural networks became quite popular (Krizhevsky, Sutskever, and Hinton 2012; LeCun, Bengio, and Hinton 2015). These models are neural networks with multiple layers of hidden nodes (sometimes hundreds of such layers). Deep neural networks—trained on large data sets through one or another learning algorithm (usually backpropagation)—have achieved great success in many areas of AI, including object recognition and strategic game-playing. Deep neural networks are now widely deployed in commercial applications, and they are the focus of extensive ongoing investigation within both academia and industry. Researchers have also begun using them to model the mind (e.g. Marblestone, Wayne, and Kording 2016; Kriegeskorte 2015).