Why Forgetting is Good for Your Memory

Who among us hasn’t worried when we’ve yet again misplaced our phone or reached back into the recesses of our mind for a familiar name and come up blank?

Our culture bombards us with directives to boost our cognitive skills and train our brains to retain information, and mental slip ups can be alarming. We worry: Is this normal memory loss or the onset of dementia?

Scott A. Small, MD, director of the Alzheimer’s Disease Research Center at Columbia University and author of a newly published book, Forgetting: The Benefits of Not Remembering (Penguin Random House 2021), has a message: For most people, not only are memory lapses normal, they’re necessary for the functioning of a healthy brain—just as important as the ability to remember.

In Forgetting, Dr. Small, the Boris and Rose Katz Professor of Neurology at Columbia, where he also holds appointments in psychiatry and radiology, translates the current science of memory to explain why forgetting benefits our cognitive and creative abilities, and even our personal and societal health.

Psychiatry News spoke with Dr. Small about the science of memory, how memory and forgetting work together, the difference between routine and “pathological” forgetting, and how we can get better at letting stuff go.

Your training, research, and clinical work has focused on neurogenerative diseases that cause dementia. What prompted you to write a book about the upside of memory loss?

The importance of forgetting is a relatively new concept for science. Until about a decade ago, normal forgetting—in contrast to ‘pathological’ forgetting that occurs in disease and with aging—was seen a passive process that served no useful purpose. Then studies began to coalesce from numerous fields revealing that there are separate molecular ‘nano-machines’ within neurons—one for memory and the other for forgetting. These findings point to an active mechanism within our brain that helps us clear out unnecessary pieces of information so that we can retain the most relevant for long-term storage.

This is an exciting discovery that presents a new pathway for memory specialists to better understand how the brain stores and retrieves memories and the human brain disorders that interfere with the mind’s ability to actively forget.

What are the positive aspects of the capacity to forget?

In a world buzzing with information, it is essential to be able to turn down the noise and discard useless details, so they don’t interfere with access to new learning or ideas. Without our awareness, and particularly during sleep, the brain is constantly sorting out which memories to keep and which can be purged and forgotten. The ability to forget helps us prioritize, think better, make decisions, and be more creative. Normal forgetting, in balance with memory, gives us the mental flexibility to grasp abstract concepts from a morass of stored information, allowing us to see the forest through the trees.

I would like to add that these benefits do not apply to the kind of ‘pathological’ forgetting commonly caused by Alzheimer’s disease and other forms of dementia, the afflictions of the hundreds of patients I have tried to help throughout my career and to whom I dedicate my book. I am talking about natural processes that we are born with and that take place in all healthy individuals and are essential for the working of the brain. 

Is there such a thing as photographic or ultra-memory?

The ability to remember exists along a spectrum, similar to other traits—like being short or tall, or gregarious or shy. Photographic memory, a memory system in which snapshots never fade, is something of a myth, more fiction than science. There are people who have highly superior memories for certain things, but not all things. For example, in rare condition known as or hyperthymestic syndrome (also known as Highly Superior Autobiographical Memory or HSAM), people can remember a vast number of life experiences in vivid detail (including inconsequential events like a trip to Target), but they’re not necessarily gifted in recalling all information, such as phone numbers or where they put their keys. Why would anyone want a photographic memory, one that gives equal access to misery and to joy? Never to forget—to hold onto hurts, petty resentments, and traumatic experiences—would be a burden, and at worst, imprison us with pain.

What is the link between PTSD and memory?

Post-traumatic syndrome disorder is a condition in which traumatic or terrifying memories remain embedded in the mind like shrapnel, impeding the brain's natural recovery. It is disease of too much emotional memory—a “brain on fire” disorder, characteristic of other psychiatric conditions, such as obsessive-compulsive disorder, anxiety disorders, and phobias.  In these disorders, key brain regions get flooded with signals that fire persistently. Conversely, “brain on ice” diseases, such as Alzheimer’s or Parkinson’s, are characterized by disrupted neuronal networks that gradually degrade over time.

I would like add a special thanks here to my colleague Yuval Neria, director of our PTSD and trauma center, who guided my analysis and writing on the topic of memory and PTSD and is the hero of that chapter.

What can we do to aid the process of letting unhelpful memories go?

One of the conclusions I came to in the book is that the best way to prevent not just PTSD but any painful memory from burning too hot is to stay social, seek friendship and love, and engage with life. Social interaction appears to quell the part of the brain that stores too many emotional memories, tamping down the fire. That’s one of the reasons the absence of human contact has been of such concern during the COVID-19 pandemic. Isolation and loneliness are associated with so many adverse consequences, from depression, high levels of anxiety, and suicide rates to reduced immune and cognitive functions.

Along with engaging in life, another path to helping the brain actively forget is to make a conscious decision to let go of resentments, grudges, and past disappointments. The more we dwell on a hurtful memory or ruminate over the events surrounding the memory, the stronger the neuronal connections become around the memory.

There is something to the old saying ‘that we need to forget to forgive.’ Most marital strife comes from the inability to forget. A couples therapist I was talking to about my book said, somewhat facetiously, that if someone could manufacture a drug that could hasten forgetting of slights and insults, they’d make a fortune!

                                                                     –  Carla Cantor