The fan effect is due to multiple mental models and is included as part of the ACT-R theory.[6] The key factors that the fan effect is dependent on are the strength and degree to which one of the variables can predict the other and the importance of the concept to a person during the retrieval process. Concepts can be better recognized by similar ideas instead of a random order of ideas. When stored in a random order, the concepts are placed in independent places in the brain instead of putting the concepts together as one unit.