Why Our Brains Are Designed to Forget

While many of us yearn to sharpen our memory, the science of sleep shows that, in fact, our brains are designed to forget—a process that unlocks the mind’s capacity to dream and think in creative ways.

Illustration by Edmon de Haro

As a memory specialist, all I hear about is forgetting. Who wouldn’t want to have a better memory? To perform better on exams; to remember with high fidelity books read or movies watched; to have more details at the tip of one’s tongue to win over minds in intellectual debates or hearts with fun facts and poetry? 

That forgetting represents a glitch in our memory systems, or a nuisance at the very least, has always been the common scientific view. However, recent research in neurobiology, psychology, medicine, and computer science has contributed to a clear shift in our understanding. We now know that forgetting is not just normal but beneficial in numerous ways. Our cognitive and creative abilities, for example, benefit from forgetting—and, perhaps counterintuitively, from sleeping

The body’s need for sleep has remained one of biology’s great mysteries. Many hypotheses have been proposed in an attempt to explain why, despite the fact that conscious awareness of our surroundings increases our chances of survival, we are forced to dedicate hours a day to a slumbering oblivion in order to survive. One hypothesis, first proposed a quarter of a century ago, has slowly…