The Disintegration of the Persistence of Memory
Why do we forget what we want to remember and remember what we want to forget?
He pulled the boy closer. Just remember that the things you put into your head are there forever, he said. You might want to think about that.
You forget some things, don’t you?
Yes. You forget what you want to remember and you remember what you want to forget.
The Road, Cormac McCarthy
Why do we forget what we want to remember and remember what we want to forget?
Forgetting isn’t simply because of a structural limitation of the brain. Through training, whether it be Anki-style spaced repetition or the use any number of strategies and mnemonics, you can substantially improve both short and long-term memory. At the extreme end of natural memory ability, a handful of folks around the world have highly superior autobiographical memory (HSAM). Those with HSAM have autobiographical memories of their entire lives, remembering mundane details of a day from years ago as easily as you recall what you had for lunch. While not actually perfect, their memories are far beyond what is considered typical.
These hyperthymesiacs don’t always consider their unusual memories to be a superpower; oftentimes, it feels more like a curse. The gashes left by traumatic memories and emotions are just as raw as the day they occurred. If you can’t forget, time doesn’t heal all wounds.
The uncanny recall of a hyperthymesiac can leave acquaintances feeling, well, creeped out. Seemingly perfect memory can make overcoming conflict in close relationships challenging as well. Imagine being able to recall in excruciating detail even the smallest of transgressions committed by a friend. What if you remembered every time your significant other wronged you—and you wronged them—years, even decades later?
Even for mere mortals lacking this seemingly-perfect recall, memory can still feel like a curse; it’s still challenging to update beliefs about a person who has hurt you, or to revisit sad or traumatic memories, or to ruminate on past decisions.
Evolution doesn’t care if we are happy. That, at least, is Rudolph Nesse’s proposition in Good Reasons for Bad Feelings, an introductory book to evolutionary psychiatry. He also stresses that the mental health problems that plague us are not adaptations themselves. “Diseases are not adaptations,” he writes. “They do not have evolutionary explanations. They were not shaped by natural selection.” Aspects of the body and mind that make us vulnerable to diseases do have evolutionary explanations, however.
If we could dump out painful memories, we’d be less likely to avoid those situations in the future, and would likely have had less success in our evolutionary environment. We’re stuck with brains that remember and assign strong weights to painful memories because it is useful to do so. The tendency to remember what we wish to forget, which makes us more vulnerable to depression and anxiety disorders, is a feature, not a bug.
Likewise, forgetting is a feature of our brains, not an evolutionary failure. Being able to pare back our memories allows us to function without drowning in information. The first person ever diagnosed with HSAM, Jill Price, has described the constant stream of recall as “non-stop, uncontrollable, and totally exhausting” and as “a burden.” While forgetting can be frustrating, it’s ultimately a part of a normally functioning brain.
One man with HSAM, Nima Veiseh, framed this challenge positively, saying, “Some say ‘forgive and forget’, but since forgetting is a luxury I don't have, I need to learn to genuinely forgive,” he says. “Not just others, but myself as well.” You don’t need perfect memory to benefit from Nima’s approach.
Trying to remember what i had for breakfast!