Both sides of the human brain appear to be physical duplicates of each other. That is, they are symmetrical. But in spite of this symmetry, they differ from each other functionally. One of the best-known differences is the left hemisphere’s superior abilities with language, and the right hemisphere’s superior abilities with spatial reasoning. For instance, it is the superior spatial reasoning of the right-side that recognizes the facial features of the friends that the language-proficient left-side verbally communicates to (in some cases where the right-side is damaged, the patient cannot recognize familiar faces or distinguish between people at all, though he can talk fluently to them).

It is well known that each hemisphere of the brain controls the opposite side of the body. The left hemisphere controls the right hand and the right hemisphere controls the left. So right-handedness and language abilities seem to be associated, at least by virtue of being controlled from the same hemisphere of the brain.

Researchers suggest that man is the only animal to show consistent use of a preferred hand for skillful actions, and that it is usually the right hand. They go on to say that the absence of a preferred hand in the lower animals is probably due to the lesser degree of upper-limb dexterity they possess compared to man. Researchers also lay heavy emphasis on the language and motor-skill centers of the cerebral cortex as being the determining factor for right-handedness in man. However, might this preferred-handedness in man be due to the greater degree of social conditioning he receives than do the lower animals?

In other words, handedness may be more socially generated than physiologically hardwired into us. One can imagine a scenario where one Stone Age toolmaker is teaching a group of observers how to make a bowl. The observers are acutely interested (for it's such an important discovery!) and follow her every move with their eyes and ears, even down to the hand she uses to steady her bowl and the hand she uses to dig it out and sculpt it. Wanting to do things exactly right, her students thus begin the habit of using the same hand they saw her use for the detailed sculpting, and the same hand they saw her use for the steadying of the bowl.

The example of bowl-making here is for convenience, of course, to express a broader idea. I could easily have used another imagined scenario such as children watching adults eat and pick berries, and mimicking their preferred hands and other physical movements. I could also probably have put to even better use an example recently given me by someone else (original source unknown to me); and that is that right-handedness may have its origins in some kind of hand-signaling system that developed before speech developed, which would explain the connection of language regions to the motor cortex, the viability of languages like ASL, and the tendency for people to accent their speaking with more and more exaggerated hand-gestures as they become excited.

The fact that the majority of succeeding generations came to favor the right hand over the left might have been completely arbitrary. The ratio certainly could not have remained 50-50. It could not have stayed perfectly balanced (like a coin on its edge) and would have had to tip one way or the other as the generations came and went, passing on this bowl-making skill to an ever-increasing number of descendents. And once tipped, using the right-hand for sculpting and the left for bracing became a kind of self-fulfilling prophecy, which became tradition, custom, and mindset. This is a simple hypothesis intended to stress an important point.

There is little doubt that a synergism came into being in many areas of social life in our prehistoric days, and is continuing today throughout the world, producing and reinforcing prejudices. The prejudice toward right-handedness and away from left-handedness is a good illustration. Some examples of the influences favoring right-handedness include the placement of gearshifts, radios, and other controls, that require more finely tuned manipulation of fingers and arms, to the right of most drivers. There is a right-lane driving preference in most countries. Gauges, clocks, rulers, and calendars all incline to the right from their starting positions. We are taught to number and write toward the right. Most tools are made for right-handed people. The most used table utensils are set for right-hand use. Moreover, the word right is used to indicate righteousness, goodness, correctness, and good judgment.

It’s no wonder that people would come to favor the right hand over the left, especially when such things as witchcraft and uncleanness are associated with the use of the left hand. Hot (potentially scalding) water taps are placed to the left in homes, with the more benign cold-water tap to the right. Even the word sinistral, which means left-handed, has the same Latin root as sinister. In addition, one of Webster’s several definitions for the word sinister reads: of ill omen by reason of being on the left.

It is conceivable that, in consequence of this social attitude, man over the course of millennia so adjusted his physical actions in regard to this left-hand taboo that this adjustment came to be reflected physiologically in the body and brain, in the same general way a carpenter’s hands, over the years, will come to reflect his activity in the strength, calluses, and musculature of his hands.

This may be true even down to the genetic level where evolution, working with a social environment unfolding over millennia in favor of right-handedness, turned in that direction. And why not? Neither the principles of evolution nor those of social conditioning seem strained on this point.

Like close cousins, the speech articulation and right-hand skill centers of the left cerebral hemisphere of the human brain are adjacent to each other; and in the right hemisphere, the centers for the left hand’s manipulation of shapes and the memory for shapes are adjacent to each other. Furthermore, the centers are in approximately the same relative locations in each hemisphere. That is, a straight line running perpendicularly through the dividing line of the two hemispheres would roughly connect these right and left hemisphere centers. So they compliment not only in function but in location as well.

We can now substitute our hypothetical straight-line connection with the real corpus callosum, which is the major neuronal cabling connecting the two hemispheres and facilitating communication between the right and left-side centers in question; much like two computers being linked to each other in a peer-to-peer relationship through coaxial cabling.

To extend the computer analogy a little more, the choice of which computer serves up what functions is completely arbitrary so long as they compliment each other and further the specific goals of the person who uses the network. Perhaps in the predawn days of humankind the two hemispheres of our brain were similar to the two computers in this peer-to-peer network – each hemisphere virtually inert, blank, and free of any programs more sophisticated than basic input-output systems in the beginning. Then as time progressed through millennia, each cerebral hemisphere took on more and more programs (i.e., thought patterns or action patterns), giving each hemisphere an evermore-distinct character of its own which complimented the growing character of the other hemisphere. The actions and functions of the human being could be maximized in this way through parallel processing, just as in a computer network. The choice of what side did what – as in the case of handedness; that is, which hand steadied the bowl and which hand detailed it out – may have been completely accidental in the beginning and grew more hardwired into us as the generations progressed.

Kolb and Whishaw (1985) reported on a 13-year-old girl name Genie. From the age of two, she had been confined to a potty chair or infant crib. The father physically punished her any time she made a sound. He didn’t let anybody talk to her; though he and the girl’s older brother “barked like dogs at her.” Only after being taken into protective custody was she taught to talk. Neurological tests, then, revealed that she was learning language primarily in her right hemisphere. One suggestion for this uncommon shift to learning language on the right-side was that it may have been due to a degeneration in the left-side, because of lack of use, or even that the language areas of the left hemisphere take on different jobs when not used for language; all of which supports the supposition that language is not hardwired into any particular hemisphere but loaded in, as if software, whenever and wherever available.

Norman Geschwind (late of the Neurological Unit at Beth Israel Hospital in Boston) has pointed out in an article printed in The Oxford Companion to The Mind (New York: Oxford University Press, 1987) that extensive damage to the language areas in most adult brains leads to permanent disability. He went on to say, however, that when the left hemisphere of children is damaged after the appearance of language but before 8 or 9 years of age, the child nearly always recovers language in a period ranging from a few months to three years. He adds that the mechanisms of recovery by means of the right hemisphere are not clearly understood; but that, if they could be understood, better treatments for adult patients might be forthcoming.

This is yet more evidence supporting the supposition that language is not hardwired into any specific location of the brain – no matter how irrefutable the fact may be that it is usually found in the Broca and Wernicke areas of the left hemisphere.

One thing is certain. All the centers and functions of the central nervous system work together to bring about and maintain a state of equilibrium with the world it is an integral part of. The world outside the skin of the human being is fundamental to the human’s existence. We cannot exist in a vacuum. That is, without the outside world existence is impossible. Therefore, the outside world – including the social world – is part of the human being. The boundaries of the human, in our thinking, should be extended outward to include it. Any theories that don’t take this into account are bound for error and incompleteness because half the equation is left out.

We are linked inextricably and integrally with our environment no less than the north pole of a magnet is linked to its south pole, no matter how often we arbitrarily draw a dividing line between the two and call the one half one thing and the other half another. It will still be one whole magnet.

One final note, any left-handers reading this article who might feel a little insecure about their left-handedness should remember some famous left-handers who have graced our Earth from time to time: Albert Einstein, Henry Ford, Winston Churchill, Marie Curie, Leonardo Da Vinci, George Burns, Charlie Chaplin, Richard Pryor, Bruce Willis, Lewis Carroll, Mark Twain, H.G. Wells, Neil Armstrong, Bill Gates, Aristotle, Benjamin Franklin, Mahatma Gandhi, and Joan of Arc, to name a few.

The End