The act of retrieval can have both positive and negative outcomes. on one hand, it improves the information just retrieved and increases the likelihood it will be retrieved again, a phenomenon called the on the other hand, it harms related information causing a person to forget such related information, a phenomenon called . retrieval practice effect; retrieval-induced forgettingb. retrieval-induced forgetting; retrieval practice effectc. addition effect; subtraction principled. subtraction principle; addition effect