In AI, a hidden layer refers to the layers of artificial neurons in a neural network that are not directly connected to the input or output of the network. These layers are "hidden" in the sense that their inputs and outputs are not observable in the final output of the network.
Hidden layers play a crucial role in a neural network's ability to learn complex patterns. Each neuron in a hidden layer transforms the inputs from the previous layer and passes the result to the next layer. This allows the network to learn hierarchical representations, with each layer learning to recognize increasingly complex features.
The number of hidden layers in a network, and the number of neurons in each layer, can greatly affect the network's performance and its ability to learn complex patterns.
While hidden layers are crucial for a neural network's performance, they also pose challenges. As the number of hidden layers increases, the network becomes more complex and harder to train. This is known as the problem of "deep learning". Furthermore, the computations in the hidden layers can be difficult to interpret, making the network's decisions hard to understand.