So how do we account for our subjective experience that older adults seem to fumble with words and names? First, there is a generalized cognitive slowing with age — but given a little more time, older adults perform just fine.
Second, older adults have to search through more memories than do younger adults to find the fact or piece of information they’re looking for. Your brain becomes crowded with memories and information. It’s not that you can’t remember — you can — it’s just that there is so much more information to sort through. A 2014 study found that this "crowdedness" effect also shows up in computer simulations of human memory systems.
Recently, I found myself in an office elevator in which all the buttons had been pushed — even though there were only three of us in the elevator. As the elevator dutifully stopped on every floor, one of the people standing next to me said, "Looks like some kid pressed all the buttons." We all laughed. I thought for a moment and offered, "I was that kid about 50 years ago," and we all laughed again. And then I thought: My memories of being 10 years old are clearer than my memories of 10 days ago. Shouldn’t that seem odd?
But in the warm, familiar privacy of my own mind, it didn’t seem odd at all: I am that same person. I don’t feel 50 years older. I can see the world through the eyes of that mischievous 10-year-old. I can remember when the taste of a Butterfinger candy bar was the most delectable thing in the world. I can remember the first time I encountered the grassy smell of a spring meadow. Such things were novel and exciting back then, and my sensory receptors were tuned to make new events seem both important and vivid.
I can still eat a Butterfinger and smell spring meadows, but the sensory experience has dulled through repetition, familiarity and aging. And so I try to keep things novel and exciting. My favorite chocolatier introduces new artisanal chocolates a few times a year and I make a point to try them — and to savor them. I go to new parks and forests where I’m more likely to encounter the smells of new grasses and trees, new animal musks.
When I find them, these things I remember for months and years, because they are new. And experiencing new things is the best way to keep the mind young, pliable and growing — into our 80s, 90s and beyond.
Daniel J. Levitin is a neuroscientist and the author of "Successful Aging: A Neuroscientist Explores the Power and Potential of Our Lives," from which this essay is adapted.