The Corpus Callosum

Ambidextrous More Likely To Be Bisexual; Why Do We Care, Anyway?
 
A new study coming from the href="http://www.uoguelph.ca/" rel="tag">University
of Guelph.   href="http://www.psychology.uoguelph.ca/d_faculty/peters.html">Dr.
Michael Peters, a neuropsychologist, analyzed a survey of
about 255,000 people, and come up with some interesting findings about
human sexuality.  Among them, is the observation that
bisexuality was  significantly more common in ambidextrous
persons:

href="http://www.uoguelph.ca/atguelph/06-12-06/featureshand.shtml">On
the Other Hand

Study refutes scientific belief that left-handedness is
linked to dyslexia, homosexuality, asthma

BY RACHELLE COOPER

Contrary to popular scientific belief,
left-handedness is not linked to dyslexia, poorer spatial ability,
homosexuality, asthma or hyperactivity, Prof. Michael Peters,
Psychology, has found.

“We’ve shown on a number of tasks that there’s no difference
between right- and left-handedness,” says Peters, whose study of more
than a quarter million people is published in the current issue of
Brain and Cognition, co-authored by psychology professors Stian Reimers
of University College London and John Manning of the University of
Central Lancashire.

The study did show, however, that individuals who didn’t favour either
hand for writing had significantly poorer spatial performance in a
mental rotation task and significantly higher prevalence of
homosexuality, bisexuality, hyperactivity, dyslexia and asthma than did
individuals with clear left- or right-hand preferences…

The survey also asked participants to self-identify their sexual
orientation as heterosexual, homosexual or bisexual. There was no
significant difference in sexual orientation between the left- and
right-handed respondents, but both males and females who said they used
“either hand” to write were overrepresented in the
non-heterosexual categories, especially the bisexual category…

What is interesting to me about this study, is that it is based upon an
Internet survey on the BBC Science and Nature
website.    It was not advertised as study about
handedness, because such advertisements tend to draw a disproportionate
number of left-handed persons.  

Of course it is impossible to avoid sample bias.  In this
particular case, it is obvious that readers of the BBC  Science
and Nature
website are going to differ in some systematic
ways from the general population.  But at least they did some
checking to see how well the results correlated with findings in
controlled conditions, and felt that there was a reasonable
correlation.  

The story goes on to say:

“Our study shows that much greater
attention has to be paid to the definition of handedness,” he says.

Peters stresses that just because someone can write with either hand
doesn’t mean the person is homosexual, bisexual or dyslexic.

I would add this: just as the definition of handedness is not as
straightforward as one might think, so too is the definition of sexual
preference.  Some would argue that bisexuality is quite
common.  It depends on how you define it.  From href="http://en.wikipedia.org/wiki/Sexual_Behavior_in_the_Human_Male#Sexual_orientation">Wikipedia:

Sexual orientation

Probably the most widely cited part of the Kinsey Reports
regard the prevalence of different href="http://en.wikipedia.org/wiki/Sexual_orientation"
title="Sexual orientation">sexual orientations
— especially to support a claim that 10% of the population
are gay. In
fact, the findings are not so straightforward, and Kinsey himself
avoided and disapproved of using terms like homosexual or heterosexual
to describe individuals, asserting that sexuality is prone to change
over time, and that sexual behaviour can be understood both as physical
contact as well as purely psychic phenomena (desire, sexual attraction,
fantasy)[ href="http://en.wikipedia.org/wiki/Wikipedia:Citing_sources"
title="Wikipedia:Citing sources"> title="The material in the vicinity of this tag needs references to reliable sources."
style="white-space: nowrap;">citation needed
]
.
Instead of three categories ( href="http://en.wikipedia.org/wiki/Heterosexuality"
title="Heterosexuality">heterosexual, href="http://en.wikipedia.org/wiki/Bisexuality"
title="Bisexuality">bisexual and href="http://en.wikipedia.org/wiki/Homosexuality"
title="Homosexuality">homosexual), an
eight-category system was used. The href="http://en.wikipedia.org/wiki/Kinsey_scale"
title="Kinsey scale">Kinsey scale
ranked sexual behaviour from 0 to 6, with 0 being completely
heterosexual and 6 completely homosexual. A 1 was considered
predominantly heterosexual and only incidentally homosexual, a 2 mostly
heterosexual and more than incidentally homosexual, a 3 equally
homosexual and heterosexual, and so on. An additional category, X, was
created for those who experienced no sexual desire.

The reports also state that nearly 46% of the male subjects
had
“reacted” sexually to persons of both sexes in the course of their
adult lives, and 37% had at least one homosexual experience. id="_ref-0" class="reference"> href="http://en.wikipedia.org/wiki/Sexual_Behavior_in_the_Human_Male#_note-0"
title="">[1]
11.6% of white males (ages 20-35) were given a rating of 3 (about equal
heterosexual and homosexual experience/response) throughout their adult
lives. href="http://en.wikipedia.org/wiki/Sexual_Behavior_in_the_Human_Male#_note-1"
title="">[2]

The study also reported that 10% of American males surveyed were “more
or less exclusively homosexual for at least three years between the
ages of 16 and 55″ href="http://en.wikipedia.org/wiki/Sexual_Behavior_in_the_Human_Male#_note-2"
title="">[3]
(in the 5 to 6 range).

7% of single females (ages 20-35) and 4% of previously
married
females (ages 20-35) were given a rating of 3 (about equal heterosexual
and homosexual experience/response) on the 8-point Kinsey
Heterosexual-Homosexual Rating Scale for this period of their lives. id="_ref-3" class="reference"> href="http://en.wikipedia.org/wiki/Sexual_Behavior_in_the_Human_Male#_note-3"
title="">[4] 2 to 6% of females, aged
20-35, were more or less exclusively homosexual in experience/response, id="_ref-4" class="reference"> href="http://en.wikipedia.org/wiki/Sexual_Behavior_in_the_Human_Male#_note-4"
title="">[5] and 1 to 3% of unmarried
females aged 20-35 were exclusively homosexual in experience/response. id="_ref-5" class="reference"> href="http://en.wikipedia.org/wiki/Sexual_Behavior_in_the_Human_Male#_note-5"
title="">[6]

As a matter of fact, when it comes to humans, there are few things that
can be defined incontrovertably.  Gender is one of them.
 Some people, you cannot tell if they are male or female.
 That’s one of my concerns about the notion of defining
marriage as a union between one man and one woman.  Sometimes
you can’t tell.  So does that  mean that persons with
ambiguous genitalia are not allowed to get married?

Or let’s say that a woman with href="http://en.wikipedia.org/wiki/Androgen_insensitivity_syndrome"
rel="tag">androgen insensitivity syndrome
gets married, is infertile, and gets an infertility workup.
 She learns that she has one X and one Y chromosome, meaning
she is genotypically male, despite all outward appearances being
female.   Is her marriage invalid?  Has she committed
a crime?  

The study about ambidexterity and bisexuality is likely to ignite
another round of nature-vs.-nurture arguments, pertaining to whether
sexual preference is a choice or a function of biology.  Why
can’t we accept the fact that some things in nature are going to defy
our efforts at categorization?  Trying to put people into
strictly defined dichotomies is often misleading, not to mention
foolish.  Then if you make value judgments based on those
false dichotomies, you’ve cast judgment on people even though you
cannot really tell what category they belong in.

Comments

  1. #1 Michael Anes
    December 16, 2006

    This is a thoughtful post.

    First, in this case we’re actually looking at two non-dichotomies, the potential relationship between mixed handedness and people who self-describe as being at neither “pole” of human sexual preference.

    Nevertheless, I do agree that sexuality research (and sex difference research in general) is poorly reported in popular and scientific lay presses. However, I don’t think the answer is to not conduct such research nor to stop reporting it – we ought instead to make absolutely sure science education in this country is top-notch, along with the reporting!

    We ought to care deeply about these issues; handedness and language lateralization can reveal key insights into our evolutionary history; along with paleoneurologists and sex researchers we have a grand interdisciplinary team of folks looking at our development ontogenetically and phylogenetically. Hormones play key yet ill-understood roles in our development and behavior and are funamentally related to brain development, pair-bonding; lots of important dimensions of human experience!

    The list of reasons why this kind of work should be considered basic science is a mile long.

  2. #2 ebohlman
    December 16, 2006

    From what I can tell, this study appears to be a “data dredge” in which correlations between handedness and various other attributes are all computed and then the researchers pick the ones that came out significant. The problem is that such a process practically guarantees that spurious significant correlations will be found; as such the only reasonable conclusion that can be drawn from a data dredge is that certain associations need to be further studied.

  3. #3 Joseph j7uy5
    December 16, 2006

    ebohlman is correct; this is a very important point. If you have a large enough data set, somewhere in there, there will be some apparent correlation just by chance.

    (If you flip a coin enough times, sooner or later you will get ten heads in a row. The odds of that are pretty low in a small series, so when it happens, it seems to mean something. But in a large series, it could be completely meaningless.)

    Those correlations then can be used to formulate hypotheses, which, need to be validated with prospective studies.

    If I had been writing a real article, not a casual armchair-musing blog post, I would have dug up the original research, rather than merely reading a press release. I would have examined more closely the authors’ claim that they cross-checked these data with other data collected in controlled conditions.

    Those are things that would happen in a good peer review process. SOmeone who has more time and interest to devote to it is welcome to do so. My purpose, though, is not so much to see if his findings are right or wrong; rather, me purpose was to use the study as a springboard to a discussion about the hazards of pidgeonholing people, then making value judgments based upon those faulty classifications.

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