Unlike elephants, humans forget. All the time. We worry about it, too, wondering if memory lapses might signal dementia.
But there’s a positive side to forgetting. Forgetting, neuroscientists are discovering, may be just as important a component of our memory system as remembering. The ability to forget allows us to focus on the most important information that we need to make better decisions.
Background: Most people, including many brain scientists, assume that it’s always a good thing when people can remember as much information as possible for as long as possible. Our brains have distinct mechanisms for storing memories, and they have been extensively studied. But there is growing evidence that our brains also have distinct mechanisms for memory loss, that is, for forgetting. Why would that be?
Research: Neuroscientists at University of Toronto evaluated the scientific literature about both remembering and forgetting to figure out what benefit there may be in having brains that can hold on to some memories and let others go. They published their findings in a “perspective” essay in the journal Neuron.
Finding: One of the mechanisms that allows us to forget is the weakening or elimination of the connections among neurons in which memories are encoded. Another mechanism is the creation of new neurons. As new neurons integrate into the hippocampus—a part of the brain that’s key to memory—the new connections “overwrite” the memories that were stored there, making those memories harder to access.
Why do we have these forgetting capabilities? The authors propose, based on new research, that the goal of memory is not to record and replay the most accurate information over time—rather, it’s to guide our ability to make the most intelligent decisions by retaining only the valuable stuff. Forgetting allows us to better adapt to new situations by letting go of outdated and potentially misleading information. It helps us hang on to the essential information so that we can recognize patterns. And forgetting allows us to generalize past events to new ones by eliminating details that are so specific they don’t apply widely.
Surprising finding: A good night’s sleep is key to forgetting irrelevant details—and holding on to the important stuff.
Bottom line: It’s important that our brains forget irrelevant details. Don’t automatically worry when you forget the small stuff—it could simply mean that you’re better able to handle the big stuff.
Worried that your forgetting goes beyond the normal? See Bottom Line’s article, “Worried About Your Memory? What’s Normal…and the Signs of Real Trouble.”
By the way: “Never forget” may be an exaggeration, but elephants can apparently recognize and keep track of the locations of as many as 30 companions at a time! Imagine having to remember the whereabouts of 30 of your friends at all times. Elephants’ memory skills are pretty impressive.