memory and the middle-aged brain


by carolyn mathews

Today, after inadvertently choosing the longest line in the grocery store, I suffered an embarrassment when it was time to pay with my ATM card. I completely forgot my PIN; the same PIN I have had for three years and use several times a week! The exact combination of numbers was tucked away securely in the recesses of my brain, but for some reason, I could not access it.

Does this kind of memory lapse sound familiar? Perhaps like some of my clients and personal friends, you have forgotten your own phone number when someone asks for it. Or, horrors – you forget someone’s name even though you have known them for years. Moreover, perhaps you are in your 40s, 50s, or 60s. Welcome to one of the hazards of middle age!

Recently I have been reading articles and books regarding brain fitness and cognitive abilities in middle- and old-age. This topic has been of interest to me since I started my doctoral degree in clinical psychology. My curiosity now focuses on how brain functioning influences older workers. One of the books I recently read is Brain Rules: 12 Principles for Surviving and Thriving at Work, Home, and School by John Medina, PhD. Medina is a “developmental molecular biologist focused on the genes involved in human brain development…” according to the bio offered at the back of his book. He is based in the Seattle, WA. area and often gives public talks about brain function. The book is fun to read, as Medina makes a complex topic very accessible to those of us who are not brain scientists through great anecdotal stories and an easy-to-understand summary of research.

Medina explains we have short-term and long-term memory. Throughout our workday, we often engage our short-term memory, also referred to as “working memory” by some psychologists and neurologists. Working memory allows us to temporarily store and manage information so we can complete complex tasks, such as learning. Medina describes working memory as, “a busy, temporary workspace, a desktop the brain uses to process newly acquired information (p.124).”

So, working memory allows us to learn in the moment, but in order to remember it, we must encode it. Encoding occurs in within seconds of learning. It takes information from the temporary file on your brain-desktop and moves it into a file folder on your brain-hard-drive so you can retrieve it later. According to Medina, elaborate encoding allows us to personalize information through meaning and context; the more elaborately we encode, the more likely we will be able to remember the information later. Furthermore, we are even more likely to retrieve the information if we can duplicate the environmental conditions. However, this may pose a problem for those people who are genius thinkers in the shower…

Those memories that survive the first few moments are eventually relegated to our long-term memory, explains Medina. Sometimes it can take years for a memory to become “fixed.” Fixed they may be, but those memories may become less accurate as the facts become less clear over time. It turns out the brain stores new knowledge and past memories together, and any gaps of information are quickly filled by old knowledge. To make long-term memory more reliable, Medina suggests we incorporate new information gradually (no more all-nighter cram sessions) and repeat the new information in timed intervals.

But what about forgetting? I didn’t forget! It turns out those of us middle-aged and older are too hard on ourselves. To forget is part of the memory process and plays an important role in our ability to process information. Medina cites research on the different types of forgetting, such as tots (tip-of-the-tongue), absent mindedness, and misattribution, among others. Have you experienced some of these?

Again, using the brain-as-computer metaphor, forgetting  erases those bits of information no longer needed and makes room on our brain-hard-drive by de-fragging the information. There is just not enough “cognitive space” for everything we learn; forgetting is a way we prioritize events or information, Medina asserts. Information that ensures our survival gets top-billing, whereas things deemed irrelevant to survival are dropped to make room for new information. In essence, forgetting things at work, for instance, means we free up space to learn and retain new things.

What I learned about memory by reading Medina’s book can be summed up this way:

  • Elaborately encode: Personalize information as much as possible by relating it to meaning and context
  • Learn things in smaller bits instead of cramming your brain with information at once
  • Repeat information at timed intervals to ensure more reliable memories (although research has not figured out optimum time between intervals)
  • It’s okay to forget – in fact, it’s necessary!

These tidbits can help all of us learn, and remember what we learn, whether at work or home.

As for my PIN, I used my psychological capability of resilience (of which part is adaptability) and chose to pay for my groceries with “credit” instead of “debit.” I wonder what I learned when my brain dropped my PIN?


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