This post by Linda Geddes at newscientist.com is interesting if you are curious about the chemical side of creativity…

According to the research, high levels of a chemical, which seems to increase creativity in really intelligent people, has the opposite effect in those of average intellect:

“THERE may be more to creativity than simply letting the ideas flow- brain measurements of a “creativity chemical” are revealing a complex interplay between ingenuity and intelligence. While high levels of the chemical in a certain part of the brain seem to increase creativity in really smart people, the reverse is true in those of average intellect.

high levels of a chemical, which seems to increase creativity in really intelligent people, has the opposite effect in those of average intellect:

N-acetyl-aspartate is found in neurons and seems to be associated with neural health and metabolism. Rex Jung at the University of New Mexico in Albuquerque and his colleagues already knew that high levels of NAA in the left parieto-occipital lobe, which coordinates sensory and visual information, were associated with intelligence.

To investigate whether NAA also plays a role in creativity, Jung’s team measured NAA levels in various regions of the brain in 56 men and women aged 18 to 39. They also tested the volunteers’ general intelligence and, more specifically, their capacity for divergent thinking, a factor in creativity that includes coming up with novel ideas, such as new uses for everyday objects.

Overall, volunteers’ creativity scores correlated with levels of NAA in a brain region called the anterior cingulate gyrus (ACG), which regulates the activity of the frontal cortex – implicated in higher mental functions. But while low levels of NAA in the ACG correlated with high creativity in people of average intelligence, in people with IQs of above 120, the reverse was true (The Journal of Neuroscience, DOI: 10.1523/jneurosci.0588-09.2009).

Jung speculates that if there is less NAA to regulate frontal cortex activity in “average” brains, they are freer to roam and find new ideas. In highly intelligent people, however, tighter control over the frontal cortex seems to enhance creativity. Perhaps this is because they are more likely to come up with new ideas anyway, and the tighter control allows them to “fine-tune” that ability.

“People say you have to let your mind wonder freely to be creative,” says Jung. “For people of average intelligence, perhaps it’s true that you need to utilise more areas of your [frontal cortex] for something truly novel and creative to emerge, but in more intelligent folks, there’s something different going on.”

Paul Howard-Jones of the University of Bristol, UK, agrees that different cognitive processes may underlie creativity in people with different IQs. “This backs up behavioural evidence for a threshold in IQ, beyond which the relationship with creativity changes,” he says.

However, both Howard-Jones and Kenneth Heilman at the University of Florida caution that, since we don’t fully understand how NAA affects neurons, Jung’s conclusions remain speculative.

Heilman adds that it would be interesting to test whether NAA also correlates with a facet of creativity known as convergent thinking – the ability to bring lots of individual factors together into a single idea.

Jung also believes his findings could shed new light on what made the brains of creative geniuses like Einstein tick. “I don’t think his IQ was ever tested, but it was likely around 120 – high, but not stratospheric,” he says. “I would have loved to see what his ACG looked like, as IQ alone did not get him there, in my opinion, but rather intelligence plus creativity.”