There is a long history of research investigating the rates of right- and left-handedness among sufferers of various diseases and disorders. For this reason, I have been waiting for someone to publish a study connecting handedness to COVID. I recently discovered such a paper, but the focus of the article was a surprise. ¹ Unlike studies of the past, it did not attempt to investigate the handedness of COVID sufferers in order to claim that one handedness type was more susceptible to the disease. Rather the authors took an approach that looked at the cultural milieu of a state in the USA, the presence of certain handedness types in that state, and compliance with directives aimed at curtailing the spread of COVID. These are the elements of the study.

Tight vs. Loose Cultures: Researchers have ranked cultures in terms of sociopolitical environments. Societies that face consistent threats, such as natural disasters or warfare, are classified as ‘tight’ cultures with strict regulation of citizen behavior. Cultures not facing such threats are called ‘loose’ with fewer restrictions on citizens and a greater tolerance of deviance. Researchers have provided ‘tight’ versus ‘loose’ scores for all 50 of the states in the USA.

Consistent vs. Inconsistent Handedness: Researchers report that individuals with consistent handedness display more cognitive rigidity. They are less open to new ideas and to evidence that might change their existing position on an issue. Those with inconsistent handedness display cognitive flexibility.  They are more prone to updating their beliefs based on new information. The authors of this study suggest that left-handedness can be used as a proxy for inconsistent handedness because 72% of left-handers are classified as inconsistent in their hand use as opposed to only 40% of right-handers.

The authors examined COVID vaccination and mask-wearing rates and compared these to the cultural scores (tight versus loose) and the rates of handedness (right/consistent versus left/inconsistent) in the 48 continental states of the USA. The authors argued that compliance with pandemic public health information requires cognitive flexibility to update opinions and beliefs as the situation evolves. They theorized that individuals with left/inconsistent handedness are more likely to follow the directives of public health officials as compared to those with right/consistent handedness.

The authors found that right/consistent handedness in general was associated with lower adherence to mask mandates. States rated as ‘tight’ and with higher rates of right/consistent handedness had lower vaccination rates. According to 2021 data, Maine, Vermont, and Connecticut had the highest vaccination rates in the USA. These states are classified as ‘loose’ by the cultural score and have higher than average (over 10%) rates of left/inconsistent handedness. In contrast, Alabama, Mississippi, and Utah classified as ‘tight’ and with lower-than-average rates of left/inconsistent handedness had the lowest vaccination rates in the USA. In general, states with higher ‘tight’ scores also tend to have more residents with right/consistent handedness.

The authors propose that the psychological traits of a population should be taken into account when designing public health messages. Research indicates that individuals with consistent handedness are more likely to comply with directives that emphasize the benefits of adherence (you will stay healthy from COVID, you will prevent sickness in others) rather than messages that concentrate on the risks of noncompliance (you will get sick, you will make others sick). Shocking images of corpses in body bags and risk messaging seem to be particularly ineffective in changing the behavior of individuals with consistent handedness.

¹ Christman, S.D., & Prichard, E.C. (2023). Right-tighty, lefty-loosey: relation between societal tightness scores, left-handedness rates, and COVID-19 outcomes in US states. Laterality: Asymmetries of Brain, Behaviour, and Cognition, 28, 285-304. https://doi.org/10.1080/135765X.2023.2244729