On the Other Hand: The Left-Hander Syndrome

Having been a multimedia teacher for more than a decade now, I have been intensely interested in the phenomenon of creativity. One interesting link is the right-brain idea for creative people, and that includes left-handedness (as the left hand is contralaterally controlled by the right hemisphere). The usual rate of left-handed people is around 12% in Western Europe and the US, and as low as 2% in countries like Korea and China.

When I ask my students in my multimedia classes (around 12 per group), I typically get two or three people to raise their (left) hands. This would make around 20% of students, which is considerably higher than the average. Of course, the link between creativity and left-handedness is well-known. Some of the most celebrated musicians, like Paul McCartney and Jimmy Hendrix were left-handers. And the list goes on from Leondardo da Vinci to Marie Curie. Left-handers are often found more frequently among extremely high IQ people.

I am not left-handed myself, but this high rate has made me research the topic more in-depth. So I read On the Other Hand by Howard I. Kushner and The Left-Hander Syndrome by Stanley Coren. As the title says Coren writes in the tradition of left-hander pathologizers and he associates left-handedness with a variety of problems:

• More Likely to Have Allergies
• More likely to have Autism and other forms of Neurodiversity
• More Prone to Migraines
• More Likely to Suffer Sleep Deprivation
• More Likely To Be Alcoholics
• Poorer academic performance (e.g. at vocabulary tests)
• Tend to Reach Puberty Later Than Right Handers

I have discussed all of these “symptoms” in connection with my hunter-gatherer hypothesis. In a nutshell: people have different traits according to our ancestral mode of subsistence: hunter-gathering, farming and herding. All of the above “problems” are also typical “hunter-gatherer type” problems. As a teacher, I am in particular interested in cognitive and learning differences. Hunter-gatherer types are likely to have a “mapping” learning style whereas farmer types have a “packing” style, i.e. farmer types have an advantage when it comes to rote learning, whereas hunter-gatherer types have an advantage when it comes to making novel connections. This difference could explain why HG types often tend to underperform in school, where rote learning is frequently required.

I also hypothesised later puberty for HG types. Coren found exactly this to be true for left-handers:

When we analyzed our data, we found that left-handed women were 59 percent more likely than right-handed women to have their first menstrual period after they were fourteen years old. This result can be interpreted as meaning that left-handed women are developing physically at a slower rate than their right-handed counterparts.(The Left-Hander Syndrome)

However, whereas Coren sees “slowed development” as pathological, I see it as normal development as hunter-gatherers had most likely a slower life-history strategy than early farmers and herders. A slightly slower development (e.g. shorter stature compared to same-age peers in childhood) and later puberty would only be the natural consequence of a slightly slower life-history strategy.

When I ask my students about left-handedness one pattern characteristically emerges: the highest frequency of lefties is among HGs, followed by pastoralist types and farmer types have the least incidence of left-handedness (this frequency is actually the inverse of actual frequency). I started to check the incidence among different ethnic groups. The Hadza hunter-gatherers actually have one of the lowest rates of left-handedness. On the other hand so do traditional farmer societies like the Zulu, who are typically the ones who most strongly disapprove of left-handedness:

If a Zulu child persisted in eating with his or her left hand, the child’s left hand was placed in boiling water. “By this means the left hand becomes soscalded [...] In contrast with the Zulu, the Khoisans of South Africa, according to a 1938 study, seemed unconcerned with the distinction between right and left.37 Writing in the American Anthropologist in 1898, another observer found some tolerance toward left handers in Native American cultures. Left-handers seemed common, he wrote, and the terms for “left” and “left-handed” in Native American languages do not have the strongly negative meanings found in most other languages. [...] Daniel Brinton concluded that Native Americans were more likely than Europeans to be left-handed or ambidextrous. (On the Other Hand)

So, even if the Hadza have few lefties, other forager groups, like Native Americans have more lefties than average. And even if there is no consistent pattern regarding handedness, there is a consistent pattern regarding attitude: farmer societies tend to discourage left-handedness. This is still common practice in countries with a long history of farming, e.g. China and Korea. The Toradja (indigenous farmers) of Indonesia consider left-handers stupid and Zulu practises (placing left-hand into boiling water) are straightforwardly barbaric.

Kushner recounts that the Zulu have a high incidence of childhood stuttering, which shows strong relatedness with being forced to use the right hand. Stutterers are 50% left-handed. Stuttering has dramatically decreased since schools in Western countries have given up enforcing right-hand use.

By the way, this is one thing I share with lefties: I used to stutter in childhood. Another thing I have in common with lefties: I had difficulties telling left from right (left-right confusion). This is another common phenomenon in neurodiverse people: ASD, ADHD and dyslexia.

So, could right-brainedness be at the basis of neurodiversity? My research showed that the right-brain idea may actually not be much more than a metaphor. What really may cause left-handedness is weaker lateralization (cross-lateralization) or less dominant hemispheric control. This also seems to be the case in other forms of neurodiversity: ASD, ADHD and dyslexia.

I don't think that left-handers have any pathology. However, they are typical "orchid children", i.e. they may have poorer or better life outcomes depending on their environment (fertile soil). All in all the relationship status between science and lefties is set to “it’s complicated”. As far as the hunter-gatherer hypothesis is concerned: even though not all lefties are hunter-gatherer types, there are signs that a lot of them are: the link to neurodiversity and later puberty are just two of them. Another one is the difficult relationship lefties often have with authority and conformity. As hunter-gatherer types they have a stronger “egalitarian instinct” that isn’t really compatible with authority (unless it stems from competence). Hunter-gatherers are typically also more freedom-loving (nobody should tell anyone what to do) and less conformist than farmers, who accept authority and hierarchy more easily.