Tuesday, July 19th, 2016
In order to remember, we need a set of mechanisms that allows us to select and target the memories we want, and allow them to win out over competing but irrelevant memories. So, initially, any act of retrieval is very resource intensive and places heavy demands on attention mechanisms in the prefrontal cortex.
Remembering something actually has a cost for memories that are related but irrelevant. But this cost is beneficial: The brain’s ability to weaken unimportant memories and experiences enables it to function more efficiently in the future.
Any act of remembering re-weights memories, tweaking them to try to be more adaptive for the next time you try to remember something. The brain is plastic—adaptive—and one feature of that is not just strengthening some memories but also suppressing or weakening others.
This function helps the brain; it doesn’t have to work as hard in the future when it tries to remember an important memory because the competing but irrelevant memories have been weakened. Memories change in both directions—they get both stronger and weaker—and this allows the brain to use less of its computational resources to recall what’s important, thereby making them available for other processes.
Memory allows humans to be predictive about what’s likely to be relevant to them as they go through life. What forgetting does is allow the act of prediction to occur much more automatically, because you’ve gotten rid of competing but irrelevant predictions.
Summing-up: The brain’s ability to suppress irrelevant memories makes it easier to remember what’s really important.