The Age of Sinistrality

On the near extinction of left-handers in the Industrial Age and their remarkable resurgence

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Previously on Our Long Walk:

• The rise of the African Crocodiles: African countries face many challenges, but like the Nile crocodile thriving in rough, turbulent waters, the continent is becoming more adept at turning these challenges into opportunities. The smart investor should take note.

• #Econhist papers I (mostly) admire, Jan 2024: From newspapers to antitoxins, from Egypt minorities to solar eclipses, the 'American Way' to pre-Enlightenment war, and much more.

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I must confess, I’ve always been slightly jealous of left-handed people. With the shift from pens to keyboards in the office, the subtle charm of discerning a left-hander has diminished, though a brief visit to a coffee shop can help.

My fascination, perhaps, stems from a simple desire to be special – in Western cultures, merely 10 to 13% of the population are left-handed – and, I suspect, from a vague notion that left-handers ‘think differently’. We now know that human handedness is closely linked to brain lateralization, where left-handedness often indicates right-hemisphere dominance, especially in language-related activities. Research suggests that the corpus callosum, the structure connecting and regulating processing between the brain’s two hemispheres, is on average 11% larger in left-handed individuals. This could lead to left-handers having higher levels of creativity.

But it makes little sense to be jealous of left-handers because, in truth, they have it pretty tough. Scissors, golf clubs and card machines are awkward to use, the buttons on computer mice are all wrong and guitars, violins and pianos all require you to play more with your ‘wrong’ hand. Studies indicate that left-handers generally have lower outcomes compared to right-handers in areas such as cognitive scores, earnings, and human capital. Left-handers face challenges in manual tasks and have a higher incidence of work and machine-related accidents, possibly due to an inherent disadvantage or the widespread use of tools and machines designed for right-handers. But, on the upside, university-educated left-handers often earn higher wages and are disproportionately represented at the top of the ability distribution, exhibiting traits like creativity, competitiveness, and leadership skills, which can contribute to innovation and economic growth.

This difference between manual and more creative tasks is also, according to a 2023 paper in the Journal of Economic Growth, the reason for a remarkable turnaround in the fortunes of left-handers over the last two centuries.¹ What few people know, is that left-handers disappeared almost entirely from the population a century ago, falling from around 10% of the population to almost 2%. As the graph shows, since the early twentieth century, though, the population of left-handers recovered to its original 10%.

The three authors – Fabio Mariani, Marion Mercier and Luca Pensieroso – have a theory of what happened. They argue that left-handedness had no significant impact on productivity or wages in pre-industrial societies, resulting in equal reproductive success for left- and right-handers, with society maintaining a stable rate of left-handedness. However, with the advent of industrialisation, left-handed workers faced challenges in serial production and using complex right-hander-designed tools, leading to lower income and potentially reduced attractiveness in the marriage market, thereby decreasing their fertility compared to right-handers. As societies developed and education became more prevalent, skilled workers of both handednesses began having fewer but more educated children, followed by unskilled right-handers, leading to a temporary increase in fertility rates among left-handers. Eventually, as more people became educated and manual ability became less crucial, income gaps and fertility differences between left- and right-handers diminished, again stabilising the proportion of left-handers in the population.

Not only does this theory explain the decline and rise of left-handedness but, the authors argue, it can also explain changes to economic growth over time. They posit that in the early stages of industrial development, the prevalence of left-handedness negatively impacts economic growth due to left-handers’ lower productivity in manual tasks and the prevalence of right-hand-oriented tools. However, as societies advance and prioritise human capital and education, the inherent qualities of left-handers, such as creativity and leadership, become significant contributors to economic growth and innovation.

They then dive into the data to prove their hypothesis. To do so, they use a two-pronged approach. They first conducted an analysis using data from the National Geographic Society Survey (NGSS), which provided information on the prevalence of left-handedness in different U.S. states across several decades. Coupled with this, they examined state-level economic data, specifically output per worker, to measure economic performance. Their initial findings indicated a positive correlation between the prevalence of left-handedness and economic growth from 1990 to 2000; to put a number on it, a one percentage point increase in the share of left-handers is associated, on average, with a 3.8% faster growth. This suggests that left-handers' unique traits could contribute positively to growth in the later stages of economic development, where cognitive abilities are more valued than manual skills.

The authors also need to show, however, that the relationship between left-handedness and economic growth evolves over time. To delve deeper, they employ an econometric model that accounts for various other factors, revealing a non-monotonic correlation between left-handedness and growth: initially negative when manual skills were paramount in less skilled economies, but becoming positive as economies developed and shifted focus towards human capital and intellectual abilities. This change over time aligns with their hypothesis that left-handedness can be a hindrance in the early stages of industrialisation but becomes an asset as economies evolve and prioritise innovation and cognitive skills.

That left-handers matter for economic growth must have policy implications. It seems sensible that education systems be tailored to accommodate different learning styles, including those prevalent among left-handers, thereby enhancing their creative and innovative capabilities. In places with large industrial workforces, adapting workplace environments and tools to suit left-handed employees could boost productivity and ensure safety. And given most countries’ eagerness to attract diverse talents and skills that will enrich their cultural and intellectual fabric, a novel idea could be to consider left-handedness as ‘a positive attribute’ in immigration policies.

As economies evolve to reward creativity, so will left-handers’ value increase. Welcome to the Age of Sinistrality.

An edited version of this article was published on News24. Support more such writing by signing up for a paid subscription. The image was created with Midjourney v6. Prompt: An African left hand holding a takeaway coffee cup that says ‘ECONOMIC GROWTH’.

1. Mariani, F., Mercier, M. and Pensieroso, L., 2023. Left-handedness and economic development. Journal of Economic Growth, 28(1), pp.79-123.