The brain can be trained at any age – the question is how. Crystallized intelligence is when the brain remembers relatively unchangeable facts, such as geographical locations or properties and traits of objects and living things. Fluid intelligence is being able to use crystallized intelligence to solve problems or adapt to changing circumstances. Throughout the range and mix of crystallized and fluid intelligences’ is the ability to pay attention, especially to increasing number of “moving parts” of information according to the level of difficulty.
A great trend in brain training, to use these forms of intelligence appropriately and pay attention, is brain games that test and challenge memory. N-back and dual n-back games are the technical terms, better known as games such as Bejewelled Blitz or any of the games on Lumosity. The argument is that playing these games will strengthen the brain, and most likely the strengthening will help stave off dementia.
However, consider learning a musical instrument instead. Being able to play an instrument (well) requires a tremendous amount of brain effort. The mind has an incredible number of things to keep track: the eyes reading the sheet music, the hands and fingers moving independently of each other, keeping to the timing and rhythm, maintaining good sound – and if playing with others – being in sync with other instruments. No other activity requires such an intricate puzzle of constantly moving parts, especially in an artistic manner.
From a practical level, brain games are generally a solitary activity. There is not really much social interaction, which is why sometimes the attention level that is strengthened does not translate to real life. Learning an instrument can be much more practical, and it connects people to others who have the same interest.