Anterograde amnesia: the loss of the ability to assimilate or retain new knowledge. Retrograde amnesia: the loss of memory for events that have happened in the past. Long-term memory (ltm): the system that is responsible for storing information for long periods of time; archive of information about past events in our lives and knowledge we have learned. Long-term memory covers a span that stretches from about 30 seconds ago to your earliest memories. Although all of these memories are contained in ltm, recent memories tend to be more detailed, and much of this detail and often the specific memories themselves fade with the passage of time and as other experiences accumulate. Although retaining information about the past is an important characteristic of ltm, we also need to understand how this information is used. We can do this by focusing on the dynamic aspects of how ltm operates, including how it interacts with working memory to create our ongoing experience.