Published reports linking left-handedness to various deviant behaviors have existed in the scientific literature for over a hundred years. Twenty-first century research efforts differ from previous eras because recent papers have used samples from large databases (such as the UK Biobank) or meta-analytic paradigms to summarize findings from many published studies. Researchers now have access to samples of left-handers numbering in the thousands, group sizes not available in earlier years. It is not surprising that these recent studies have failed to confirm the previous associations found between left-handedness and various pathologies.
Research conducted in Australia fits this description. ¹ The researchers used information from the Household Income and Labour Dynamics in Australia (HILDA) database, a longitudinal study of participants in Australian households begun in 2001. In 2016, the writing hand of 15,376 participants was observed and used as the measure of handedness side. This classification method resulted in 13850 right-handers (90%) and 1526 left-handers (10%). In addition to age and sex, participants were queried about the frequency of drinking alcohol using a graded series ranging from ‘never‘ to ‘everyday‘. Participants also described how much alcohol they consumed during each drinking occasion, ranging from ‘1 drink‘ to ‘13+ drinks‘. The authors classified drinkers as risky if they consumed 4 standard drinks each day, and high risk if they drank double this amount or 8 standard drinks each day.
The results indicated that left-handers were more likely to engage in heavy drinking (8 or more standard drinks each day) than right-handers. The left-handed group contained more males (55%) than the right-handed group (46%). Also, the left-handed sample was younger than the right-handed sample (17% versus 23% of participants over 60 years of age). When age and sex were removed from the predictive equation, the authors found that left-handers were no more likely to engage in high-risk drinking than right-handers.
The researchers also explored another potentially addictive behavior, gambling. Participants were classified as gamblers if they reported the purchase of any type of lottery tickets or participation in bingo and/or casino or sports betting. They were called problem gamblers if they answered ‘yes’ to questions such as ‘Have you borrowed money or sold anything to get money to gamble?‘ There was no difference in gambling behaviors between left- and right-handers.
These results indicate that left- and right-handers are similar in their drinking and gambling behaviors. The findings also emphasize the importance of going beyond simple comparisons between left- and right-handed groups. The authors found that group differences in alcohol consumption disappeared when age and sex were removed from the analysis. Such a result becomes possible when studying a left-handed group of 1526 participants. Large samples of left-handers are found more frequently in recent published papers with the establishment of population-sized databases around the world.
¹Callinan, S., Leggat, G., Van Egmond, K., & Lindell, A. (2022). The impact of handedness on health risk behaviours and socio-economic outcomes. Personality and Individual Differences, 187, 111411. https://doi.org/10.1016/j.paid.2021.111411