The Wages of Sinistrality: Handedness, Brain Structure, and Human Capital Accumulation

Abstract

Roughly 12 percent of humans are left-handed, with somewhat higher rates among males than females (Vuoksimaa, Koskenvuoa, Rosea, and Kaprio 2009). For much of history, left-handedness was viewed with deep suspicion. During the Middle Ages, left-handed writers were thought to be possessed by the Devil, generating the modern sense of the word sinister from sinistra, the Latin word for left. The English word left itself comes from the Old English lyft, meaning idle, weak, or useless. The French word for left, gauche, also means clumsy or awkward. Similarly negative connotations of the word left are found in numerous languages, including German, Italian, Russian, and Mandarin (Coren 1992).Superstitions about left-handedness take numerous forms (Perelle and Ehrman 2005). In many Middle Eastern countries, food and drink should be taken with the right hand and bodily functions performed with the left. Hindu tradition forbids the left hand from performing many of the central religious rituals. Left-handedness suggested to Eskimos that the individual was a sorcerer and to colonial Americans that the individual might be a witch. The Jewish scholar Maimonides listed left-handedness among the 100 blemishes that disqualified someone from being a Jewish priest.Left-handers have often been compelled by their parents and schools to use their right hand for writing and other tasks. Such practices are now more common in developing countries so that, for example, 11 percent of Turks and 16 percent of Nigerians report attempts to switch their handedness earlier in life (Medland,

Handedness, Earnings, Ability and Personality. Evidence from the Lab

“…[1] conducted a study on the relationship between handedness and several policy-relevant outcomes. Representative survey data on about 40,000 young adults, with age ranging from 20 to mid-30s, were obtained from multiple sources: the UK (National Child Development Study and the British Cohort Study) and the US (Children and Young Adults and National Longitudinal Survey of Youth).…”

“…Evidence on about 2,000 young adults in the US (National Longitudinal Survey of Youth) aged 28-35, i.e. on average slightly older than those in the data sample in [1], shows that L males with college education obtain 15% higher wages [2]. In contrast, no significant difference is observed for females.…”

“…Results showing that L are over-represented among talented and creative individuals [10, 18] are based on a small number of observations and are overall little robust, as shown in [1], while over-representation among low ability individuals is more robust [1, 19]. Related evidence on differences in cognitive ability by handedness is mixed.…”

“…Related evidence on differences in cognitive ability by handedness is mixed. Some studies show higher ability for L [10] while others lower [1, 11]. …”

“…Survey evidence on young adults in the UK and in the US shows that L earn 10% less, are more frequently in low-skill jobs, with little gender difference, and, in addition, have lower cognitive skills [1]. Comparable results on young adults in the US, although slightly older than in the previous study, show that L males with college education obtain 15% higher wages while no difference is observed for females [2].…”