We've all come to believe that as people get older, they inevitably lose their mental abilities, from speeded responses to the infamous inability to remember names. Occasionally, researchers challenge this set of assumptions, showing that age changes in everything from brain volume to higher-level intellectual skills are preserved in some people well into the 80s, 90s and beyond. However, the considered wisdom is certainly on the side of aging bringing with it mental decline.
Now, the considered wisdom may be changing. University of Tübingen linguist Michael Ramscar and his colleagues (2014) systematically compared computer simulations with human performance data on aging in areas such as memory for names, ability to learn novel associations and even speed of responses. Their basic argument is that as you get older, your storehouse of knowledge and experience continue to grow exponentially. As a result, it takes you longer to sift through all that information when you're trying to recall one specific thing. Like a crowded file drawer, each item becomes more difficult to pull out compared to a drawer that's nearly empty.
Let's start with the case of people's names, always a sore spot for people with memory complaints. According to Ramscar and his co-authors, the reason you would have more trouble remembering the name of someone you meet when you're 50 than you did when you were 30 is due to the sheer number of people you've met over your life. It would be statistically impossible for you to remember the many thousands more people you've met over the course of your life. Therefore, forgetting one person's name, or even 10 or 20, doesn't mean your mind is shot.
Similarly, the ability to learn new paired-associates, a frequent test of learning, can be more difficult for older adults because they have acquired so many more associations throughout their lives that have to be forgotten in one of these lab tasks. This is very much the same as might happen to you when you're used to going the same way to your neighborhood coffee shop. When the sidewalk closes due to construction, you have to go a different way. However, because that habit is so well-formed, there will invariably be days when you head out taking the old, familiar path before realizing your way is blocked.
Letter classification is another task commonly used to demonstrate slower mental processing for older adults. You're shown a series of two letters from a set of five, presented in uppercase or lowercase, and asked to decide in each case if the pair of letters are the same. Older adults take longer on this task, according to the Ramscar study, because they've formed more paired-letter associations throughout their lives. As you get older, you also learn more abbreviations which pop into your head at the same moment when you're faced with making this lexical decision. It's not a long hesitation, but long enough to show up as significant when we're talking about differences on the order of a few milliseconds.
Older adults may also perform more poorly in a lab task because they don't believe in their own abilities. When I was conducting my dissertation research on memory in older adults, I found that many of them were worn down by anxiety about their supposedly failing memories. The fact that they were all in an "elder learning" university setting should have contradicted this fact for them. However, in their own minds, their elder learning just wasn't up to snuff. Ramscar and his colleagues also consider the weighting down of someone's mind with test anxiety to be a source of performance interference in older participants.
The Ramscar study goes a long way toward countering what we thought we knew about the aging mind. Let's hope that it's soon replaced by a more optimistic view that respects the growing wisdom that you can accumulate over your lifetime.
Ramscar, M., Hendrix, P., Shaoul, C., Milin, P., & Baayen, H. (2014). The Myth of Cognitive Decline: Non-Linear Dynamics of Lifelong Learning, Topics in Cognitive Science 6 (2014) 5-42 DOI: 10.1111/tops.12078
If you'd like to read more about this study, please check out my Psych Today blog posting.