Why do some memories stick with us while others fade?
Ohio State psychologist Per Sederberg theorizes that long-lasting memories are created from associations with other memories, according to Science Daily. This interconnectedness with other memories makes it easier for our minds to get back to a given memory. "You want to build a rich web," he said, and connect memories in multiple ways. He compared a particularly memorable memory as a big city, with many roads that lead to it. By contrast, forgettable memories are likened to "desert towns" with only one road in.
Another factor in determining the degree of memorability is a balance between novelty and familiarity. Novelty tells us what is important to remember, and familiarity tells what we can ignore, but also helps the mind retrieve information later. If you have too much novelty and there is "no way to place it in your cognitive map," or in other words, no context in whcih to place it and make sense of it. Too much familiarity and the information is discarded as unnecessary and lost.
Context is key to retrieving memories. Sederberg says that the most memorable experiences are those that arise in a "familiar and stable context" but also "violate some aspect of what we predict would occur in that context," in other words, have a degree of novelty or even peculiarity. "Those peculiar experiences are the things that stand out, that make a more lasting memory," he said.
Memories help define who we are and can inspire emotions that are not just ephemeral but carried throughout a lifetime. There is still much research to be done on the cognitive neuroscience of emotional memory, or the recollection of personal memories from the past and emotional associations.