Question

Would someone be able to explain to me or point me to some resources of why (or situations where) more than one hidden layer would be necessary or useful in a neural network?

Answer 1

1. That’s more similar to the way the brain works (which might not necessarily be a computational advantage, but a lot of people are researching NN to gain insight about the way the mind works, rather than to solve real world problems.
2. Its easier to achieve some kinds of invariance using more layers. For example, an image classifier that works regardless of where in the image the object is found, or the object’s size. see Bouvrie, J. , L. Rosasco, and T. Poggio. “On Invariance in Hierarchical Models”. Advances in Neural Information Processing Systems (NIPS) 22, 2009.