Scientists have long taken for granted that the human brain progressively weakens with age and that no new brain cells can grow after a person reaches early adulthood. Those assumptions have been questioned in recent times, and there is in fact compelling evidence to the contrary. Still, it remains a sad truth that our learning abilities and memory capacities lessen as we grow older, and there is an abundance of research going on trying to figure out how the deterioration can be slowed down, if not altogether stopped.
To determine the rate of decline, people with age-related mental problems are usually subjected to a barrage of tests focusing on short-term memory, responsiveness and problem solving. However, most of these tests are not specifically designed for older individuals but are more or less applicable to any age group. Critics say this may disadvantage people whose brains still function perfectly well with regards to their daily routines, even though they may perform poorly in an artificial test environment.
According to a new study from Germany, there may be other reasons than natural degeneration why seniors appear to become increasingly forgetful, unable, for instance, to remember names and dates, or a particular word in conversation. Linguistic researchers from the University of Tübingen who conducted the study suggested that because educated older adults have often larger vocabularies than their younger contemporaries -- simply by virtue of having lived longer -- their brains may require more time to search and retrieve some words or phrases, which can delay their responses.
So, in addition to a certain amount of slowing brain activity that may be inevitable as time passes, it may also be that the aging brain undergoes subtle structural changes to deal with the wealth of information that was accumulated over a lifetime.
There are different kinds of intelligent activities, some geared towards short-term memorization (e.g. remembering names, dates, telephone numbers, etc.), others to acquire skills, knowledge, and expertise. What the German researchers are proposing is that an increase of the latter may come at the expense of the former, meaning as people's brains store more old information, the capacity to add new and less relevant data diminishes.
In other words, the brain may need to make storage choices as it grows older. In fact, it is not unlike a computer hard drive that is getting close to capacity, resulting in reduced processing speed.
These changes in performance do not happen overnight but likely take place throughout adulthood. In the later stages of life, unfortunately, the disadvantages become more evident, which then can appear as cognitive decline, even though it may not be.
As intriguing as this theory may sound, it is obvious that additional research needs to be done to shed more light on these highly complex issues. Still, exploring new ways to better understand what happens to both our bodies and minds as we are able to further and further extend the average human life span, is an undertaking that should be pursued with urgency.