You’re already late. Impatient friends are clogging your phone and the bus you were supposed to be on just rolled by. As you scurry around your apartment, trying to get your things and yourself out the door, your keys are nowhere to be found. How is that possible? You threw them on the couch, or the desk, or the...
Welcome to working memory. This transient state of memory consolidation is like your brain’s holding cell. Here, the prefrontal cortex and other brain regions try to make sense of our experiences and decide which ones are important enough for precious long-term storage. Those that make the cut are encoded into the hippocampus for future retrieval. Those that don’t are forgotten about, and can sometimes make you unfashionably late. However, since most experiences from everyday life are trivial, forgetting is actually a good thing.
This has to do with the way memory is stored in the first place. Although a convenient analogy, the brain does not store individual memories away one by one in a filing cabinet. Instead, every time you recall a memory, your brain reconstructs it. This is good and bad. It saves on space in the three-pound real estate we’re limited to. However, we embellish details and reconstruct the story we want to remember, not the reality. So even though two people may have the same experience, their memory of the event will be their own biased version. Forgetting certain bits can give us a rosy recollection.
No story about memory would be complete without mentioning Henry Molaison, or H.M. Desperate to find relief from his severe epileptic seizures, he underwent brain surgery that removed his hippocampus and amygdala. Remarkably, the seizures stopped. Regrettably, he could no longer form new memories. This is known as anterograde amnesia and the daily challenges people with this affliction face were accurately portrayed in the movie Memento. Because of H.M. we understand the working basis of memory and which brain areas are involved. While forgetting trivial details is efficient, forgetting all new experiences can be harmful.
Extreme forms of forgetting include brain disorders like Alzheimer’s. Though devastating, new insights about this degenerative disorder continue to be discovered. Last month, research from the lab of Nobel Prize winner Eric Kandel identified a gene for a protein that may play a role in memory decline. Older mice with memory deficiency had lower levels than younger mice. After researchers boosted the gene in older mice, they exhibited improved memory ability on par with younger mice. This shows the many possible breakdowns in proper memory consolidation.
No doubt, working memory is vital for everyday decision making, information processing, and reasoning. It helps take previous knowledge and experiences to make sense of the present world around us. Whether you like it or not, your brain has a beautifully streamlined and efficient way to keep you from becoming overwhelmed with all the information bombarding us. One day, there may even be practical applications of this process. Learning to forget may help treat post-traumatic stress disorder or depression, by helping people purge negative memories. Until then, be more mindful of your keys, but thankful the unnecessary details free up space for the memories needed for survival.