What Makes A Brain Gifted?
As I've said, you cannot have functional or behavioral differences (such as being smarter) without some kind of corresponding difference in the brain from a more typical brain. As understanding of the causes of those differences improves, researchers will know better how to identify and develop them. On the whole, brain differences fall into four distinct categories. They are morphology, operations, real estate, and electro-chemical cellular functions, or M-O-R-E as a way to remember them easily.
- Morphology: Size, quantity, and shape of brain structures
- Operations: Neural efficiency and speed of internal connectivity in the brain
- Real estate: Strategic differences in which or how brain areas are used
- Electro-chemical cellular function: Differences in electrical and chemical activity
The difference most associated with gifted children is the effectiveness with which they learn; as a generalization, they pay closer attention, absorb information, stay focused, learn the interrelationships more quickly, and remember longer. Those are the observable consequences of the four differences I just described. The following sections describe how each of them plays out.
The first category—brain morphology—refers to the shape, size, and boundaries of structures within the brain. Some correlations suggest that more brain volume equals more computing power.17 Total brain volume accounts for about 16 percent of the variance in general intelligence scores. If this study was true, you'd also expect overall head size to correlate with intelligence, and it does.18 Interestingly, students with AD/HD have both lower overall IQ scores and smaller brain volume, by 3 to 4 percent.19 Data like this suggest at least some kind of a correlation between overall computing capacity and the brain's morphology. Bigger head size does increase the chances for greater IQ. This obviously does not mean that all melon-headed kids are geniuses, but the correlations are well above chance levels.
Another set of animal studies measured (postmortem) the total number of both neurons and glial cells (the highly important support tissue) in rats. In the gifted, there were far more glial cells (more than double!) as compared with the nongifted learners. But what about humans?20 As a vivid example, when Marian Diamond studied a sample of Einstein's brain tissue in the mid-1980s, she found that his brain had more glia per neuron than did the average brain (73 percent, compared with eleven others) in one area: the left inferior parietal lobe (Figure 6.1).21 This difference exceeded the expected ranges for both age and individual variability and may be typical for the frontal area of exceptionally gifted people—or it may have been the specific area Einstein used for complex mathematical theories.
As a historical note—and evidence of the difficulty many have in accepting the idea that exceptional brains can differ physically from the norm—it's interesting to observe that Diamond's paper ran into a firestorm of publicity. Her fellow scientists concocted headlines based on her findings ("Einstein's Extra Brain Cells: The Secret to His Genius!") as icebreakers in their presentations, setting crowds of skeptical researchers roaring with laughter.22 Diamond herself never generalized her results to all geniuses, merely saying that they were potentially meaningful, and her work has since been vindicated. Today, we do know that larger numbers of glial cells are correlated with improved learning and memory.23 In another study with highly gifted individuals, there was a significantly greater level of individual variability, especially in the right hemisphere.24 This may reflect space, time, and sensory processing skills.
Surprisingly, gifted brains also include larger proportions of "extreme neurons"—those very small and very large neurons. These are ones that seem to either start off that way, enabling a greater number of connections, or develop in ways that may have some additional processing capacity. In another study that compared people with strongly creative, highly gifted talents to a control group of average performers, postmortem evidence revealed a much more customized and specialized brain.25 More cortical fields were streamlined, there were greater numbers of pyramidal neuron glial cells, and there was much greater distinctiveness of how the neurons were grouped. This suggests the extensiveness to which gifted people use particular areas of the brain. All told, the giftedness may be more likely a combination of differences or a threshold that needs to be reached. There are correlations for it in a larger-than-typical brain or in those with unusual neuronal development, and it may have more glial cells than a typical brain.