- competition between correct/incorrect information
- similar activation/context
- e.g. person has a new boyfriend/girlfriend. Always mixing up previous/current name
- proactive interference (forward)
- previous is clashing with new knowledge
- retroactive interference (backward)
- old knowledge overwritten by new knowledge
- forgetting triggered by learning or processing new information
- interference works only on simple memories
- complex memories are immune to interference
- enough connections = no simple interference