Re: Left/Right Culture

JOHN LANGDON (LANGDON@GANDLF.UINDY.EDU)
Mon, 28 Mar 1994 11:16:03 -0500

In message Seeker1 writes:
> 1. Is there a connection between the predominance of right-handedness and
> the preference for the right as a spatial orientation? Is the breakdown of
> southpaws vs. righties (I understand left-handers are about 10% of the
> population in the U.S.) the same all over the globe? Is handedness found in
> our primate cousins, and in what distributions? Most importantly, why are
> humans very rarely ambidextrous? And why do most societies read from left
> to right, with a few exceptions?
>
There is a big literature on primate handedness which has not found consensus.
Yes, there is evidence of handedness, but it may be qualitatively different from
ours.

> 2. Since the left side of the body is controlled by the right brain, is
> there any link between denigrating the left side of the body and the
> preference our society has for left-brain (analysis, computation, etc.)
> over right-brain (synthesis, pattern recognition etc.) functions? Is there
> any basis to the belief that left-handers are more right-brain-oriented,
> and therefore more creative, analogical, inutitive, etc? Is there any basis
> to the belief that females, homosexuals, or artists are more likely to be
> left-handed?
>
> 3. Language processing generally occurs, even in southpaws, in the left
> hemisphere. In some people, it occurs in the right hemisphere. Do these
> people process language any differently than the rest of us? Why is it that
> in many linguistic systems, "right" means both "to the right" and "correct"
> or "proper"?

In light of this correct observation, I suggest you reconsider the right/left
dichotomy. Of the 15% or so of the population that is non-right-handed (and
therefore called left-handed), only about one quarter (4%) of these are true
left-handed individuals. That is, cerebral dominance and functions are reversed
with language processing in the right hemisphere. I imagine a developmental
pathway that creates them as the same as for true right-handers but in mirror
image. The others show some degree of ambidexterity, but fall on a spectrum so
that each individual is unique. Some may be truely ambidextrous (no hand
preference), while others, including myself, are selectively ambidextrous
(prefer some tasks with one hand and other tasks with the other). Ambidexterity
suggests a different developmental explanation-- one that has a theoretical
potential to produce slightly different cognitive abilities.

Correlates of left-handedness, such as larger corpus callosum (also cited for
women) and greater tone discrimination, are reported with no specifications as
to whether the study population was really left-handed or merely ambidextrous. I
don't believe such results will be meaningful until such discriminations are
made.



JOHN H. LANGDON email LANGDON@GANDLF.UINDY.EDU
DEPARTMENT OF BIOLOGY FAX (317) 788-3569
UNIVERSITY OF INDIANAPOLIS PHONE (317) 788-3447
INDIANAPOLIS, IN 46227