Music & Intelligence: Will Listening to Music Make You Smarter?:

As Rauscher explains in a later paper, the Mozart Effect was studied only in adults, lasted only for a few minutes and was found only for spatial temporal reasoning. Nevertheless, the finding has since launched an industry that includes books, CDs and websites claiming that listening to classical music can make children more intelligent.

The scientific controversy - not to mention the popular confusion - surrounding the Mozart Effect, has given rise to a corresponding perplexity for parents. They wonder: "Should my kids even bother with music education?"

In fact the answer to this question is still a resounding yes, since numerous research studies do prove that studying music contributes unequivocally to the positive development of the human brain. Other researchers have since replicated the original 1993 finding that listening to Mozart improves spatial reasoning. And further research by Rauscher and her colleagues in 1994 showed that after eight months of keyboard lessons, preschoolers demonstrated a 46% boost in their spatial reasoning IQ, a skill important for certain types of mathematical reasoning.

In particular, it is early music training that appears to most strengthen the connections between brain neurons and perhaps even leads to the establishment of new pathways. But research shows music training has more than a casual relationship to the long-term development of specific parts of the brain too.

In 1994 Discover magazine published an article which discussed research by Gottfried Schlaug, Herman Steinmetz and their colleagues at the University of Dusseldorf. The group compared magnetic resonance images (MRI) of the brains of 27 classically trained right-handed male piano or string players, with those of 27 right-handed male non-musicians.

Intriguingly, they found that in the musicians' planum temporale - a brain structure associated with auditory processing - was bigger in the left hemisphere and smaller in the right than in the non-musicians. The musicians also had a thicker nerve-fiber tract between the hemisphere. The differences were especially striking among musicians who began training before the age of seven.

According to Shlaug, music study also promotes growth of the corpus callosum, a sort of bridge between the two hemispheres of the brain. He found that among musicians who started their training before the age of seven, the corpus callosum is 10-15% thicker than in non-musicians.

At the time, Schlaug and other researchers speculated that a larger corpus callosum might improve motor control by speeding up communication between the hemispheres.

Since then, a study by Dartmouth music psychologist Petr Janata published by Science in 2002, has confirmed that music prompts greater connectivity between the brains left and right hemisphere and between the areas responsible for emotion and memory, than does almost any other stimulus.

Janata led a team of scientists who reported some areas of the brain are 5% larger in expert musicians than they are in people with little or no musical training, and that the auditory cortex in professional musicians is 130% denser than in non-musicians. In fact, among musicians who began their musical studies in early childhood, the corpus callosum, a four-inch bundle of nerve fibers connecting the left and right sides of the brain, can be up to 15% larger.

While it is now clear from research studies that brain region connectivity and some types of spatial reasoning functionality is improved by music training, there is growing evidence that detailed and skilled motor movements are also enhanced.

Apparently the corpus callosum in musicians is essential for tasks such as finger coordination. Like a weight-lifter's biceps, this portion of the brain enlarges to accommodate the increased labour assigned to it.

In a study conducted by Dr. Timo Krings and reported in Neuroscience Letters in 2000, pianists and non-musicians of the same age and sex were required to perform complex sequences of finger movements. The non-musicians were able to make the movements as correctly as the pianists, but less activity was detected in the pianists' brains. The scientists concluded that compared to non-musicians, the brains of pianists are more efficient at making skilled movements.