Cognitive development is an amazing thing. Babies start off understanding very little about the world around them, and largely unable to consciously learn or remember anything. As development continues, we increasingly demonstrate an enormous capacity to learn, communicate, explore, and understand mental and physical aspects of our environments. However it might seem that, at a certain point, cognitive development comes to an end. After that point, our trajectory over time just reflects aging. The term cognitive decline refers to the idea that, much like the physical health of our bodies eventually deteriorates with age, so too does our brain (and therefore our cognitive abilities). Today we will discuss some misconceptions surrounding this idea.
It is untrue that cognitive development ends at a certain age. Neurogenesis—the development of new neurons in the brain—does tend to slow down with age, but to varying degrees. And it never seems to stop completely. We are constantly learning and forming new memories, and continued developments can be observed as changes in the physical structure of the brain throughout the lifespan. Things that researchers have shown to cause physical development in adult brains include playing a musical instrument, learning to juggle, exercise, meditation, or simply being in a more enriching environment. These are just examples. Anything new that you do will probably physically change the brain in some way, even if only the slightest bit.
Neuropsychology is a branch of psychology that aims to understand the relationship between brain functioning and behavior. One of the most popular methods in this field is neuropsychological testing. These are behavioral tests that are designed to measure the functioning of specific parts of the brain by measuring psychological processes that are known to reflect them. These tools can be very useful for diagnosing and understanding cognitive impairments related to brain injuries or disease. And as we get older, we also seem to start performing worse on these tests. Cognitive decline.
So, we know that certain parts of the brain are engaged during certain psychological processes, and we know that neuroplasticity and neurogenesis are possible. Can we create tasks that target certain parts of our brains in order to give them a healthy workout? Yes, it should be possible. And there certainly have been attempts, including a number of very popular websites. However, the evidence so far is not promising. Most of the studies so far find that participants tend to improve with practice on the “workout” task, but there are no such improvements on different measures that should be affected if a specific type of cognition is indeed improving. Such training tasks do not seem to affect general intelligence either.
Is cognitive decline a myth?
We all have the same basic stereotypes about older people (and, yes, older people also tend to endorse them). Old people are slow, forgetful, and mentally inflexible. In our own experiences as we age, we may seem to fulfill the stereotype through confirmation bias. For example, if you think that you are becoming more forgetful, you might also become more likely to notice when you forget things (or pay less attention to all the times that you do remember things). Or you might actually become more forgetful because of the stereotype. This study found that reminding older adults of elderly stereotypes caused impaired memory performance (though at least partially because they may have used different strategies to learn and remember).
In the next 60 seconds, how many words that start with the letter “A” can you list? It turns out that older adults outperform middle-aged and young adults by a wide margin. This and other results have recently led researchers to argue that cognitive decline is actually just a myth. And their theory is fascinating.
The basic argument is that older adults seem slower or more forgetful precisely because they know more. If our minds and brains are constantly learning and developing throughout the lifespan, there is going to be some baggage. The larger your vocabulary, the harder it is to find the specific word that you are looking for. The more people you have met during your lifetime, the harder it becomes to remember all of their names. The researchers were able to confirm these basic predictions across an extensive series of experiments.
The same basic experiments that confirmed the predicted differences between young and old were also put to test as computer simulations. For example what happens when you try to search a large database of words? It takes longer to search than a smaller one. Even with the exact same hardware, the process slows down as you add more information. This suggests that getting slower with age might not actually reflect a decline in brain functioning.