Psychology
The world is not built for the 10% who are left-handers, but there can be advantages.
The world is not built for the 10% who are left-handers, but there can be advantages.
Acouple of years ago, my wife and I had a serious discussion: whether to build or buy the house we want to live in to our dotage or make our present house what we want. My preference: work with what we’ve got, partly out of fear of what the housing market might do and also because I hate moving house. I still have boxes of stuff that haven’t been unpacked since the last move.
So, last summer involved numerous gardening projects: building planters, retaining walls and suchlike. I took the odd day off each week and set my out-of-office message to tell people what I’d be doing (and not just ignoring their emails). I have been intrigued by how many questions I got asking how it was going. Had I chopped off a finger yet with that new circular saw I’d mentioned?
But no, I haven’t lost a limb yet. I may not be particularly competent, but I am careful. It also helps that I’m right-handed, because even though we may be having increasing discussions about gender fluidity, all-genders toilets and suchlike, in the world of power tools, there really are only the right-handed. Before the outcry,
I should acknowledge that this is not entirely true. A small number of brands make left-handed power tools, but they’re extremely rare and even harder to find here in New Zealand. Bunnings sells left-handed tin snips, and Mitre 10 offers a niwashi garden tool but nary a power tool. Which is part of the reason that left-handers are, apparently, more likely to die in accidents. Not because they’re careless, but because operating a circular saw backwards is dangerous. Handedness is a “behavioural preference” – we have a feeling that we’re more comfortable with the pen in one hand rather than the other, and for about 10% of folks, that preference is for the left hand. This in turn reflects the dominance of the left hemisphere in fine motor activity, such as writing. Left hemisphere, right hand. Right hemisphere, left hand.
Just as London cabbies have bigger-than-average hippocampi (an important brain structure for spatial awareness), left-handers’ right motor cortex is bigger than their left, while the reverse is true for righties.
We’ve known for a long time about the lateralisation of handedness: that one hemisphere is dominant and that other lateralisations also tend to cooccur with handedness, such as with language comprehension and production, which are also more likely to be atypical among left-handers. Unsurprisingly, we’re now finding that
Left-handers are more likely to die in accidents – not because they’re careless, but because operating a circular saw backwards is dangerous.
other lateralisations also occur.
For example, for around half a century, the left hemisphere was believed to hold responsibility for approachrelated emotions – such as happiness (“let’s pat the cute puppy”). But the right hemisphere supervises avoidance-related emotions such as disgust (“let’s not pat the possum roadkill”).
Cornell associate professor Daniel Casasanto has compared this with classical sword fighting – we hold our shield, or avoid emotions, on our non-dominant side and wield our sword and approach-related emotions on the dominant. This “sword and shield” hypothesis suggests that we’d expect a reversal of this traditional lateralisation among left-handers, and that’s exactly what Casasanto and his colleagues argue they find.
As well as being good for pub quizzes, this has implications for the use of one tool for treating stubborn depression and anxiety: electrical – and more recently magnetic – stimulation of the left hemisphere in the hope of encouraging approach emotions and behaviours. If the “patient” is left-handed, you’re more likely to miss your target.
In sport, left-handedness can be a help or a hindrance. Left-arm bowlers can be very handy in a game of cricket and southpaw boxers a real handful – in no small part because of their relative rarity. Cricketing great Sir Richard Hadlee batted lefthanded but bowled (mainly) right. Pub quiz time again.
Right now, I’m building a deck, so there’s still a chance of some ACC-related time off work …