As we approach another anniversary of the pandemic’s onset, many of us are reflecting on the past two years and thinking about the ways the virus has altered our lives. More than 950,000 Americans have died. Many more have lost a loved one, and millions are still grappling with the lingering after-effects of infection.
As we begin to move toward a post-pandemic future, it is vital that we remember the toll this virus has taken. The lessons of this pandemic should be carried with us so that unlike what happened after the 1918 flu it doesn’t fade from history and so we can honour and memorialise those we have lost.
It is also inevitable that over time, many of our memories of these difficult years will fade. As a neuroscientist who studies memory and memory disorders like Alzheimer’s, I find this fact perhaps counter-intuitively comforting. I have come to understand, through new research, that there is a danger in remembering too much and that forgetting is not only normal but in fact necessary for our mental health.
It used to be thought that forgetting anything from minor things like the name of a casual acquaintance to the more painful loss of cherished memories experienced by my patients was caused, to varying degrees, by a failure of the brain’s memory mechanisms. But new developments in neuroscience over the past decade or so refute this simple idea. Neurons contain what are sometimes called nano-machines that are dedicated to the construction of new memories. But scientists have recently discovered that neurons are also endowed with a completely different set of nano-machines designed for the opposite purpose: to carefully disassemble and thus forget components of our stored memories. In light of this new and growing body of research, normal, everyday forgetting can no longer be thought of as a malfunction of our memory machinery; instead it should be considered a healthy and adaptive part of our brain’s normal functioning. Memory and forgetting work in unison. We depend on our memory to record, to learn and to recall, and we depend on forgetting to countervail, to sculpt and to squelch our memories. This balancing act is, as it turns out, vital for our cognitive functioning, creativity and mental health.
Of course, there are unhealthy kinds of forgetting. Alzheimer’s disease, for one, targets memory mechanisms and causes them to fail. But in other disorders, it appears that the brain’s forgetting mechanisms break down. The psychological condition that perhaps best exemplifies what can happen when people don’t forget properly is PTSD. While it is often beneficial to remember the facts of a traumatic experience, sometimes even in pointillist detail, it is equally if not more important to the healing process to let the emotional valence of it fade. If we don’t, we can get stuck in total emotional recall, reviving our distress in perpetuity.
Forgetting protects us from this debilitating anxiety not by deleting memories but by quieting their emotional scream. The same is true for more run-of-the-mill emotions. Intuitively, it makes sense that we sometimes need to let go of hurt and resentment to preserve close friendships and that we need to forget in order to forgive. “Letting go” is one of the many colloquialisms that implicitly nod in recognition and gratitude toward our brain’s forgetting mechanisms.
In patients with PTSD, the area of the brain that stores fear memories is highly active, suggesting that the individual cannot properly engage the brain’s fear forgetting system and therefore cannot let go of the high anxiety associated with the memory of the traumatic event. Complex disorders should not be oversimplified, but it is possible to think about PTSD as a disorder stemming from too much memory, caused by an inability to forget a traumatic experience in a healthy way. Turning down activity in this brain region induces a healthy ability to forget feelings of fear.
