Scientists find plenty of correlations between memory and associations. Not all information you once learnt is lost forever. Memories may just be inaccessible. Then they pop up during, for example, a dialogue with someone. You suddenly remember a movie you saw a few years ago or a book you read long ago.

Some people are trying to create their own mental library. However, they soon get disappointed. This cannot be an effective way to memorize things. Sooner or later you’ll see that your memory cannot keep everything and you forget something anyways.