*Learning is a process by which the free parameters of a neural network are adapted through a process of stimulation by the environment in which the network is embedded. The type of learning is determined by the manner in which the parameter changes take place*
1. The neural network is **stimulated** by an environment
2. The network undergoes **changes in its free parameters** as a result of this stimulation
3. The network **responds in a new way** to the environment as a result of the change in internal structure
