  The ability to learn tasks in a sequential fashion is crucial to the
development of artificial intelligence. Neural networks are not, in general,
capable of this and it has been widely thought that catastrophic forgetting is
an inevitable feature of connectionist models. We show that it is possible to
overcome this limitation and train networks that can maintain expertise on
tasks which they have not experienced for a long time. Our approach remembers
old tasks by selectively slowing down learning on the weights important for
those tasks. We demonstrate our approach is scalable and effective by solving a
set of classification tasks based on the MNIST hand written digit dataset and
by learning several Atari 2600 games sequentially.
