there are several explanations of why we forget. Passive-decay theory says that learning causes a physical 'trace' in the brain that decays with time. repression theory says that we purposely push unpleasant or unacceptable memories into our unconscious mind. systematic-distortion theory says that our memories may be distorted by our values and interest, to be consistent with how we want the memories to be or how we think they should be. interference theory says that forgetting is due to problems in retrieval the information, and that we can remember almost anything if given the right cues.