This is not about politics (primarily), but about the brain.

According to New Age thinkers, the left brain hemisphere thinking is linear, logical, rational, while right hemisphere thinking is artistic, holistic, and imaginative. After reading the chapter in “The Scientific American Book of the Brain”, I have to disagree, especially about the “imaginative” part.

It is the Left Brain Integrator which is the organ of imagination, even sometimes confabulation. It seeks patterns avidly“and in their absence, it invents them. It thinks in symbols (as in language, which it alone possesses), and is thus uniquely human. It can tell lies, and even get to believe them as false memories. The right brain, in contrast, is always truthful. But the left is also the seat of leaps of faith, as in hypothesis-formation (adduction) and metaphors. Without this, neither science nor poetry would be possible.

The right hemisphere is the brain that humans share with other primates, perhaps all mammals and birds. It is more truly the mammalian brain than the limbic system, to which this role is usually assigned. It is probably wrong to assume that mammals and birds have no cortex; yet the human cortex (on the left) differs profoundly.

The right brain is smart about perceiving shapes, colours. and motion, like the visual system. It is like people with an M-type EEG, who think in pictures. That is what beasts in the wild primarily need, to catch prey and avoid being prey. The P-type people tend to be poets, scientists, mathematicians, and musicians, using the left brain more than the right. The M-type people tend to be artists, sculptors, painters, and architects. And then there are the well-balanced people, who can do both moderately well, though not at genius level.

Symbolic thought entered the world with humans (as far as we know). Human brains are not only bigger, but are differently structured. Size alone is relatively unimportant.

One difference between men and women is also some difference in brain structure, though with considerable overlap. Men’s brains are more lateralized than women’s brains; i.e. the difference between the left and right hemispheres is more pronounced, sharper than in women’s brains. Women tend to be more half-and-half in each hemisphere. So women, of course, can think symbolically, but in a more integrated way, though not as extremely.

As the diagrams at the end of this article show, this can be compared with the genetic composition of the sexes. The genes in the X chromosome are fully backed up by alleles in women, while men lack the alleles for most of the genes on their one and only X chromosome. So if one of the single alleles is defective, it is nevertheless expressed, while in women the other allele would be functional. (E.g. men can have colour-blindness and sickle-cell anemia, while women are far less likely to suffer from this.)

Thus women’s brains can combine science and art more effectively, not be over-specialized, though perhaps not be top performers in either. (This is obviously an over-generalization.)

And in politics, to give this some attention, Left and Right each have part of the truth: society and individual, justice and freedom, change and stability. Perhaps we should all be Radical Middle.

In addition, it seems that the left prefrontal lobe creates an up-beat, optimistic mood, while the right prefrontal lobe generates a sad, melancholy mood. The whole prefrontal lobe interprets and elaborates emotional signals welling up from the amygdala. Certain hormones can suppress or accentuate happy or sad moods.