New Rules for Saving Your Memory

Q | Do we need to forget because we’re bombarded with so much information all the time?

A |  Yes. The brain’s computational speed is pretty slow; it can’t process all the information that’s out there. So it has to make decisions about what it will and won’t take in. Figuring out what’s relevant and irrelevant, and then subtracting the irrelevant, is some of the most important work the human brain can do at any age.

Recently we’ve learned that most midlife memory fading isn’t about memory after all. That is, it’s not about retrieval mechanisms. It turns out that what middle-life brains have a really hard time doing is blocking out unnecessary information. As you get older, you lose your filtering ability.

A good example is not remembering where you put your keys. We sometimes call it a senior moment; it feels like you’ve forgotten something. But what’s actually happening is that lots of other input is flooding into your brain, and you’re unable to turn down that noise so that you can pay attention to the thing you’re trying to remember. As you begin to lose control of controlled forgetting, your ability to attend to things—like where you put your keys—decreases because you can’t prioritize your inputs.

Q | In your book you point out that there are significant genetic and anatomical differences between women’s brains and men’s. Does a woman’s ability to filter out information break down faster than a man’s?

A |  No, not at all. Women do have a menopausal issue, and certain aspects of their changing hormone profile can amplify some of the natural effects of aging on the brain. But on the whole, the gender differences in this area are not big. More important, I think, is the fact that women assume responsibility for crucial threads in the social fabric that guys don’t. As a result, women are required to be more reliable. I’m often asked, “Can women multitask?” And the answer is no. Neither can men. The brain cannot multitask. But women often handle a variety of separate tasks during the day: They go to work, pick up the kids and still do most of the housework. It’s difficult enough to juggle all those demands when your brain is young, but as you get older, your brain becomes more easily confused by the scope of your to do list. You may, for instance, forget to pick up milk—or your kids!—on your way home from work.