Why We Forget More As We Age

Recently I discovered a scientific basis for why we forget so much as we get older. To explain this, I need to put it in biological context. A woman is born with a finite number of eggs in her ovaries. Once they’ve all made that monthly journey down her fallopian tubes (or have shriveled up in situ), there are no more eggs to be had.

It’s much the same with brain cells wired for memory. Our brains have a finite capacity for the number of things we can remember. Once our hippocampus is full (usually as we approach retirement age), there’s no more room for new stuff. Depending on your sentiments and the type of brain you have, you either fail to store any new information, or the new information bumps out something older that’s already in there.

If you’re paying attention, you’re no doubt wondering how your gray matter decides whether to refuse to remember new information vs. getting rid of something older, and what that "something older" might be. A key factor is the state of the economy when you reach your golden years.

Accountants will be familiar with two ways to value inventory: LIFO (Last In, First Out) and FIFO (First In, First Out). In an inflationary economy, companies prefer LIFO accounting. Inventory you use up is valued at the higher cost of a recent purchase, rather than the lower cost of something procured perhaps years earlier. (Yes, I know that companies can’t just switch back and forth willy nilly.)

An older brain will simply refuse to remember something new unless it’s really important. In that case, in a deflationary economy (speaking hypothetically, of course), a FIFO brain jettisons the oldest memories first, if it can find them. A LIFO-economy brain bumps out one of the more recently-acquired pieces of information. This explains why, in the real world, those with failing memories can often recall things from decades past, but not from yesterday.

Like everything else involved with gray matter, this is not a simple, clear-cut process. There’s a certain amount of emotion involved, too. If the positive emotional value of the memory about to be expunged is at least twice that of the new item, the brain will refuse the new information. Similarly, if the negative baggage of the old stuff is twice that of the incoming, it’s out with the old, in with the new. I hope you’re getting all of this.

If you’re of a certain age, expect to be forgetting more and more recent knowledge from now on. Baby Boomers have little chance of approaching retirement in a deflationary economy. Interest rates may start ratcheting up next year. If rates go up, can inflation (and LIFO memory) be far behind?

Getting back to the ovary/eggs comparison. Scientific advancements enable a woman to use a donor egg to create a baby. We need to co-opt that science for gray matter in order to counteract the forgetfulness that comes with aging. We donate blood. We donate bone marrow. Is it too much to ask to be able to donate a few cells from one hippocampus to another?

While we wait for this breakthrough, there are certain mental exercises you can do to help you retain the memories you cherish most. If you were paying attention three paragraphs back (and if you’re not functioning in extreme LIFO mode), you’ll remember that emotions can influence which older memories get expunged to make way for new ones. This tidbit is the basis for your exercises.

Decide which memories you are determined to hold onto. Pair them with some positive emotional imagery. Focus on this pairing for at least two minutes. The emotional connection will now override the LIFO/FIFO functioning of your brain. The memories you want to keep will remain, regardless of where they are in the LIFO/FIFO hierarchy.

Conversely, think of something you’re perfectly willing to forget. Pair it with something repulsive in your emotional repertoire. Focus on this pairing for at least four minutes; (bad stuff takes twice as long to jettison). The emotional connection will similarly override the hierarchy.

There you have it. A simple explanation for why we forget more as we age and easy-to-perform exercises to manage this problem while we await a scientific breakthrough to allow brain cell transplants.

In the meantime, it’s a good idea to scatter some notebooks around your house and in your car. And several pens or pencils. Write down anything really important, and then hope you don’t forget where you put the notebook. You can thank me later, if you remember.