Astrogator's Logs

New Words, New Worlds
Artist, Heather Oliver             

The Left Hand of Light

Note: An expanded, updated version of this essay has been reprinted at the Huffington Post with the title Southpaws: The Hops in Humanity’s Beer?

left-handed.jpg Those who are, like me, left-handed and older than forty probably recall being forced to write with our right hand and the frustration of using many “handed” tools, including scissors, rulers and computer mice. We also remember being told that left handers are prone to depression, immune deficiencies, shorter lives, dyslexia and a host of other woes… and no wonder, given the drizzle of harassment! Finally, there is the conflation of left with evil, wrong or inept in practically all religions and languages (sinister, gauche, linkisch…), not to mention most political systems.

The percentage of left handers hovers around 10% regardless of race and culture. The most common explanation for the persistence of the trait was that left-handed warriors had the element of surprise in primitive societies. As a result of this sneakiness, they survived long enough to leave a few like-handed descendants (notice that this explanation is exclusively male-oriented and also implies that the trait is dominant).

From my readings on the topic and my own awareness of what strengths and weaknesses I possess, I hit upon a slightly more flattering explanation for the persistence of the trait. Namely, I decided that left-handed people must be less lateralized in their thinking. This can lead (literally) to crossed wires — and hence to such outcomes as dyslexia and depression. But it can also lead to less mental compartmentalizing, more efficient multi-tasking, enhanced ability to see the big picture and to think across boundaries.

Results from recent tests in several neurobiological disciplines lend support to these speculations. Apparently, left handers do cluster at the extreme ends of the IQ range, the connections between the two sides of their brain are faster than in right handers, they often use both hemispheres for language and they excel at complicated tasks. So left handers may not just be a relic of barbaric times, after all. Instead, they may be the hops that add zest to humanity’s beer.

Here is one link to recent work:

8 Responses to “The Left Hand of Light”

  1. rocketscientist says:

    I sometimes wonder if some of these genetic trates are really so very tied to survival of the species. Couldn’t some of them be random mutations that were perpetraited by isolation and inbreeding until they became fixed in a genetic line?

  2. Athena says:

    They could be — but then the percentages would differ in different populations and handedness is very uniformly spread. You are right, not all traits need to have an advantage, especially now that humans are no longer being selected on the basis of viability. There is one gene so far associated with handedness (and with the orientation of one’s hair whorl, which has no survival value).

  3. Marie says:

    This is a tongue-in-cheek response as I am far from being equipped to respond scientifically. Because I have never associated left-handedness with anything evil or woeful, I do tend to consider California a part of the left coast and liberal political aspirations as leaning left.(*grins*) My only bones of contention with “lefties” were from my youth. Their desire to jump into a spinning rope from the opposite direction than everyone else, trying to hit a baseball or softball thrown by a “south-paw”, sitting in a conjoining desk and trying to write at the same time and last but not least sitting at the dinner table with a lefty who insists that your napkin and glass of water is theirs and giving you the elbow when they delicately lift a forkfull of food to munch.
    Seriously, this is an ideal hypothesis which illuminates a series of conjectures regarding the explanation of the trait.
    Incidently, I have too many family members and beloved friends who are left handed to be prejudiced in that regard.
    Indeed they add sweetness to my soul and sunlight to my shadows.

  4. Athena says:

    The interesting thing is that scientists still are not certain whether our closest ape relatives have a favored handedness, are ambidexterous or random.

    For the fun of it, I chose a left-handed celebrity to illustrate this post. (*smiles*)

  5. rocketscientist says:

    “They could be — but then the percentages would differ in different populations and handedness is very uniformly spread. ”

    That’s interesting! So handedness is more of a “species” trait and may even be confined to Homo Sapiens – does that indicate that the gene must have estabished itself when the species was developing tool making proficiency? Or is somehow linked to brain size or one of the various idiosyncrasies of humans?

  6. rocketscientist says:

    I wonder if Neanderthals were handed? Most likely, right? They weren’t very different from us.

  7. Athena says:

    Yes, handedness appears to be a species trait — or, rather, the gene(s) that confer it may be species-specific.  The trait may be connected to the expansion of the frontal lobe, it may be connected to walking upright. We won’t know until we find all the genes that influence it, there seems to be at least one more (and even then, we will have to figure out how it works).

    I suspect, as you do, that Neanderthals were handed, but it’s hard to tell by examining their tools or skeletons. Both are too worn for definitive assignments, plus there aren’t enough complete skeletons to establish robust statistical significance.

    We can tell the percentage of handedness in early humans from looking at the handprints that the Cro-Magnon artists left in caves. 20% of the prints were of the right hand, which falls splat in the middle of the variance across today’s populations.

    Incidentally, there are human-specific genes and the roster will undoubtedly expand after the chimpanzee genome has been completely sequenced and compared to the human. Not surprisingly, almost all of them affect brain function. I am actually working on one of them that is connected to dementia.

  8. jimenarocker says:

    Being left-handed, like yourself, I have found little harrassment in my life. The only time anyone ever mentioned my being left-handed was when they stared at me when I wrote, and hadn’t realized I was left-handed.
    Being left-handed, or right-handed, apparently just depends on what hand a baby favors in the womb, however. I’m not sure, but if that’s true, I’m not surprised.
    But, on a personal judgement, most left-handers are more interesting to me than right-handers, I’ve come to find out. It isn’t that right-handers are boring, but it’s because they’re like me, and most left-handed traits seem to speak for most left-handers, like being great at multi-tasking, and being able to visualize things clearly.