Since that time, the measurements and tests which are used to test human intelligence have come under better scrutiny, and the very young discipline of neuroscience has advanced enough to show that rather than having fixed capacities, the human brain is capable of developing greater neural nets and connections as a response to use. Many studies show this. For example, if a person loses a hand, the areas of the cortex that used to control that hand may in time be subsumed into new neural connections, developed for some other activity which the person is engaged in.
This was an astonishment to brain science, and there were even whispers and later discovery of neurogenesis -- the creation of new neurons -- though only in limited areas of the brain. Before that, it was expected that the same neurons we have at birth will last throughout our lifetime.
Neuorplasticity is one of the most wonderful discoveries ever made -- not just in relation to the physical person, but also in respect to the very question of what it means to be a human: you can change.
With the discovery of neuroplasticity, it is very natural that tests and trials would be made which measure the increases in the neuropile after engaging in certain activities. If you play piano, the cortical areas you use to perform this complex task will increase in connections and even size. The abstracts and studies on this are so numerous that it can now be said that if you engage in any activity on a regular basis, whether it is tactile or not, the brain re-organizes and re-allocates its resources to suit use. It could be described as similar to using certain muscles, which grow and quicken in response to use, and which also may decrease in size with disuse (brain atrophy is another subject, though not entirely).neu·ro·plas·tic·i·ty
the ability of the brain to form and reorganize synaptic connections, especially in response to learning or experience or following injury.
Now I will get to the point. Neurologists naturally like to announce findings of brain size changes, and present these findings as a benefit to certain activities. And there is no doubt that neuroplasticity is an established reality for us; so that these findings of increased bloodflow, size, and connectivity are indeed being detected in the human brain -- even areas of the mid-brain.
One example which I have seen in most brain books is the "enriched environment" tests on rats. It was, briefly, a finding after many experiments with rats, in which some rats were kept in cages alone with very little to do, and then of this group, some were transferred to a cage with many toys and many rats. Among the sacrificed rats, as probably many here already know, the rats in the enriched environment with increased social interactions had an increased neuropile compared to the rats kept alone.
This was immediately interpreted as scientific proof that day cares and early education led to increased brain development and therefore to increased intelligence. That is not necessarily a good conclusion for many reasons. First, the rats may have an increased brain size because they were dealing with more anti-social behavior and conflicts with rats they didn't know; and second, because any increased, regular activity at all may prove to increase the density of neuronal connections.
All of this to say that increased neural net circuitry, increased blood circulation, or even increased size in an area of the brain, are not, in themselves, good arguments for the supposed benefits of a particular activity. Rather, it is already established that our wonderful brains have the physiological power of neuroplasticity, and this ability to form new skills and knowledge, resulting in physical changes in the brain to support it, will accompany any activity that we habitually engage in. And this is true at any age, all the way into middle and late adulthood.
So we should never let the neuroscientists get away with the "it enlarges the size and connectivity" argument, when they are trying to "scientifically" assert the benefits of any particular activity.
What supports neuroplasticity in any purposeful activity is a far more important question. It already has been established that brain development is best supported by good, stable, loving bonds, a varied diet not deficient in superior proteins, B12, zinc, and salt, etc., and long periods of concentration in one's chosen interests.