(and footedness, eyedness and so on).
Is it okay to out someone for their handedness? I don’t know. Clearly I can out myself for my own handedness, which I only realised a few years ago was different from the norm because I’m cross-dominant. For most of my life I’ve assumed I’m right-handed because I write with my right hand, but there are also many things I do left-handedly about which I’ve never thought. For instance, I always use pointing devices on computers such as mice, trackpads, trackballs and joysticks with my left hand and I use cutlery the opposite way round from the usual European way. However, I’m not convinced those are genuine examples of handedness. It certainly feels awkward to use a mouse in my right hand but I made a conscious decision a long time ago to do that left-handedly because it was said that if you use a keyboard mainly for typing and it has a numeric keypad, you should use a mouse left-handedly as otherwise you will be leaning over slightly to the right all the time and it isn’t good for your posture. For that matter I don’t think using a pointing device in either hand is particularly good since I went through a phase of getting a cold left hand and that may have been due to excessive mouse use influencing the circulation to it.
My cutlery use is also kind of left-handed, but there’s a proviso there too. When I notice people using a knife and fork in the typical European way, with the fork in the left hand and the knife in the right, it looks incredibly awkward to me and I can’t empathise in that very minor way. However, it should also be borne in mind that the kind of food I eat with a knife and fork is not typically European and I could probably get away without using a knife at all much of the time. Carnists need to cut up large pieces of food with their knives, and therefore if they’re right handed it makes sense for them to use that hand, but as a veggie, most of my food is already in small bits when I serve it out and therefore a knife is often almost redundant. I often find, in fact, that I haven’t used the knife at all throughout my meal and just put it away unwashed because it’s still clean. There is said to be another factor in East Asian cuisine and etiquette here although it sounds a little like a racist myth. Supposèdly, East Asians eat with chopsticks because they want to keep weapons away from the table and all the chopping and cutting takes place in food preparation. The same is generally true of me, but I’m not aware of doing that for that reason. Additionally, I can’t use chopsticks so far as I can tell and this may be a further clue as to what’s going on, because although it’s undiagnosed I appear to be dyspraxic. It isn’t that I can’t use chopsticks specifically: I’m not necessarily that good at using any kind of cutlery, and to give myself any kind of chance at it I have to place the fork in my right hand.
Nonetheless, I do seem to be cross-dominant rather than just being accustomed to doing certain tasks a certain way round, because things like crossing legs, clasping hands and all the rest is pretty randomly distributed although I do have a preference. I have also wondered, though, whether my handedness (and the rest) isn’t so much cross-dominant as an obscure handedness I’ve heard of which sounds like it might be the same as dyspraxia called ambisinistrous. This is where both hands are like the non-dominant hand of the majority of the population. In other words, one is clumsy.
Although I don’t want to be writing exclusively about myself here, I’m going to ask you to indulge me a little longer. My mother attributes my dyspraxia and handedness to her upbringing of me, which of course sounds like the common self-blaming attitude parents have. She was herself left-handed, and grew up at a time when there was much more prejudice against left-handed people in this society than there is today, although structural prejudice still exists of course. Two illustrative stories about such prejudice from my mother and a friend of hers are that she was regularly rapped across the knuckles with a ruler for writing with her left hand, with the result that she couldn’t write straight for ages because she was forced to use her right hand, which would’ve influenced the perception her schoolwork received, and someone else was caned for drawing a picture of a man sawing with his left hand. This kind of active, conscious prejudice is so far superceded today that it’s actually used as an analogy for irrational discrimination, but it is still true that left-handedness is structurally problematised, and it may also be overgeneralised in its associations. For instance, there are office desks for computers with holes designed for mouse, monitor and keyboard cables on the right which mean that in order to use a cabled mouse left-handedly, one must trail the wire across the desk or reach over to the right, and contoured mice are usually designed for right-handed people. Similarly, I always have to swap the knife and fork over when eating at a table where my place has been set by someone who has assumed my handedness. Other examples are rife. I would expect it to come into driving and I know it applies to nibbed italic pens, which for me used to be the main pens I wrote with. There are left- and right-handed styles of calligraphy and of course there are the numerous other examples of tin openers, scissors and the like.
My mother believes that I was supposed to be left-handed but she encouraged me to be right-handed, but I don’t think this is true. According to Desmond Morris, children are born without a hand preference and later go through several phases of being left- or right-handed and then swapping for a while until it settles down completely by the age of eight or so. I think my mother observed me doing this and mistook it for me being left-handed. I don’t know if Morris’s claim has turned out to be true today.
The categories of handedness in question could be profitably enumerated at this point, bearing in mind also that they may apply to other parts of the body such as legs and eyes. These seem to be:
- Left-handed
- Ambidextrous
- Right-handed
- Cross-dominant
- Ambisinistrous
I can’t think of other categories. However, it might be possible to vary according to feet, hands and eyes, which would afford ten dozen and five possibilities, but it isn’t clear that all of those exist to me rather than being real possibilities.
I’d also like to make one more egocentric observation. There’s a category of conditions known as monothematic delusions, of which there are several types. They tend to be considered neurological rather than psychiatric, and include Capgras, Cotard, Fregoli, Intermetamorphosis, Subjective Doubles, Reduplicative Paramnesia, Mirrored Self-misidentification and Somatoparaphrenia. Although I’m not aware of having most of these, I have experienced a mild form of the last when I’ve been tired, ill or intoxicated in some way. Somatoparaphrenia is the belief that part of one’s body doesn’t belong to one, and people come up with elaborate explanations as to why they have this extra part, such as that surgeons stitched it on while they were under anæsthetic or that it’s a severed limb which is in the hospital bed with them and attempt to push it out, maybe falling out of bed in the process. I haven’t experienced that first hand, but I do sometimes have the impression that the right hand side of my body is less “me” than my left hand side. This could, though, be linked to living in a culture where text flows from left to right, which has unexpected consequences. Mirrored self-misidentification may also be relevant as although I am fully aware that the person in the mirror is me, I also think it may be significant for handedness, because when you learn to do things, you’re often doing so from a person facing you and are likely therefore to use your left hand when they use their right, and so forth. I once came a-cropper in a T’ai Chi (太極) session because I found myself mirroring the instructor rather than turning it round and trying to do it backwards, as everyone else was. I find this a little difficult to express.
Certain devices are designed for left-handed use by default. For instance, QWERTY keyboards have the three most common English letters on the left, and a rotary dial telephone is often designed for holding the handset with the left hand. However, this is sometimes because limitations of the devices require the right-handed to be disabled for them to work properly. The difficulty left-handed people have with the world of right-handed people and devices is a good parallel to structural racism. The difficulty in getting an infrared operated tap to work in a public toilet is in a way similar to the difficulty one might find opening a conventional tin with a conventional tin-opener. There are also assumptions made due to the higher association between left-handedness and certain conditions, such as schizophrenia. Also, although I’m not aware of a difference between handed reactions to certain drugs, it’s a fact that there are herbs which have different actions on left- and right-handed people and I would imagine the same is true of purified medicines.
It’s a common misconception that left-handed people are ruled by their right hemispheres and vice versa. Although there is a correlation, it isn’t that clearcut. It is true that only five percent of right-handed people have dominant right hemispheres. However, most left-handed people are also left hemisphere dominant, although they are more likely to be right hemisphere dominant than right-handed people and to have active brain regions in both hemispheres for language. Hence there’s a correlation but it isn’t particularly clear, and in a way the real truth is that most people have dominant left hemispheres. It isn’t clear how this works with the other forms of handedness.
“Handedness” seems to apply to eyes, ears, hands and feet. When it differs for ears and eyes, there can be an issue with coördination, which might apply to hands and eye as well. I seem to be left-eyed and left-eared, because I find it easier to follow speech in earphones in my left ear than my right regardless of how well I can hear in each ear. One side of human retinæ crosses over to the opposite side of the brain and the other to the other, which is an unusual arrangement but does turn up in some mammals who are not closely related to humans, such as fruit bats. Another aspect of the arrangement of sensory areas in the brain is that the touch areas are upside down with respect to the body, as is the motor cortex. This seems to be because the retina inverts the image and makes the wiring simpler, as does the fact that the sensory and motor cortices are adjacent to each other. It also explains the crossing-over, known by the fancy term “decussation of the pyramids”.
The cerebral cortex, of course, consists of two hemispheres linked by a bridge called the corpus callosum. One of the differences between female and male brains is said to be that the former have more links across this than the latter. The dominance of one hemisphere over the other only doesn’t lead to two personalities in each body because of this bridge, and presumably we wouldn’t be left- or right-handed if we all consisted of two people in one body with opposite handedness. However, marsupials have no corpus callosum but are still sometimes left-handed. Kangaroos, for example, are usually southpaws. Marsupials and placental mammals diverged in the Jurassic, so it may not be too informative that they also have handedness, but it does suggest a different cause than hemispheric dominance, as does the fact that most left-handed people have the same dominant hemisphere as right-handers. Something else seems to be going on here, and marsupials demonstrate that there can be another explanation.
Bodily asymmetry in general is a bit of a mystery. In saying this, I’m not talking about something like having four digits on one hand and five on the other, but internal organs. Most people’s hearts are slightly left of centre, their livers on the right, stomach on the left and so forth. The evolutionary pressure to make the external body symmetrical doesn’t seem to apply so much to internals, although the skeleton and muscles are almost so and the causes of them not being are linked to handedness. Most people’s spines curve slightly to the right because the muscles controlling the upper extremity are stronger on that side. There are cases of situs inversus, where the whole of the internal organs are mirrored, thought to result from a vanishing twin situation where the other twin was a mirror twin rather than identical, and also of the more serious dextrocardia, where only the heart is on the right hand side and the rest of the body is as it is in most other people. Dextrocardia usually involves other cardiac abnormalities, sometimes as such, sometimes because, as I said, the rest of the body is not mirrored so the great vessels are still in the usual places but connected to the wrong parts of the heart.
Children of left-handed parents are still likely to be right-handed, but they are more likely to be left-handed. However, identical twins can have different handedness. Some genes have been found which are associated with handedness. LRRTM1 is associated with left-handedness in people with dyslexia and PCSK6 with right-handedness in people with schizophrenia, but it isn’t clear that they have anything to do with handedness in anyone else. They might just be associated with two conditions which could be called “schizophrenia-with-right-handedness” and “dyslexia-with-left-handedness”, as it were. Genetic models of handedness cannot be simple, single allele-based systems, and this to my mind makes them somewhat like sexual orientation, which has genetic and environmental influences but the former is not based on a single “heterosexual” gene or “gay” gene. Perhaps, then, the analogy between handedness and sexual orientation can be extended considerably.
I wanted to get this out for international left-handedness day, so I’m going to cut and run for now, but I may have more to add in the near future.
A Box Of Chocolates 