Knowledge acquisition with forgetting: an incremental and developmental setting

Identifying the balance between remembering and forgetting is the key to abstraction in the human brain and, therefore, the creation of memories and knowledge. We present an incremental, lifelong view of knowledge acquisition which tries to improve task after task by determining what to keep, consolidate and forget, overcoming the stability-plasticity dilemma. Our framework can combine any rule-based inductive engine (which learns new rules) with a deductive engine (which derives a coverage graph for all rules) and integrate them into a lifelong learner. We rate rules by introducing several metrics through the first adaptation, to our knowledge, of the minimum message length (MML) principle to a coverage graph, a hierarchical assessment structure which handles evidence and rules in a unified way. The metrics are used to forget some of the worst rules and also to consolidate those selected rules that are promoted to the knowledge base. This mechanism is also mirrored by a demotion system. We evaluate the framework with a series of tasks in a chess rule learning domain.