As the director of a longevity center at a respected research institution said to me recently, "We just haven't figured out what to test. We haven't been creative enough." She was referring to our discussion of what kinds of exercises really keep our brains fit. That seems to be changing.
Jonathan McNulty of the School of Medicine and Medical Science, University College, Dublin, has tried a different approach. And it works. His team found that simple yet intensive memorization followed by a rest period resulted in ". . . both metabolic changes in the brain and improved memory performance." The 55- to 70-year-old volunteers were given six weeks for intensive rote memorization tasks, such as memorizing a newspaper article or poetry, of 500 words. They then had six weeks of rest.
Here's the kicker: when tested immediately after the memorization work, there was no change in brain metabolism or memory performance. But after the six-week rest, all of the volunteers showed improvements in verbal and episodic memory (the ability to relate story or tell a joke).
This reminds me of a trick I've long used: if I have a problem I need to figure out, I assign my brain the task, usually before going to sleep, and forget about it. Typically, later (and sometimes immediately when I wake up the next morning), a solution or at least a way of thinking about the problem pops up (without being summoned) in my mind. Our brains clearly need some down time to work on their own without our conscious interference.
Recently, there have been several studies using the Stroop test. That's the one with color words written in a different color (the word blue written in yellow, for example) and you're asked to identify the color of the letters. The distraction of automatic reading of the word makes it challenging to identify the letter color. Several researchers have shown that intensive work on the Stroop test (or similar tests or games) can substantially improve driving skills. Why? Because driving requires concentration--the ability to override distractions and automatic responses and choose the required response.
To me, these studies test the right things and are beginning to prove that practice on cognitive process (fluid intelligence) is just as important as acquired knowledge (crystallized intelligence). It takes both to keep our mental edge.