Welcome to 2021! My first post of the year deals with footedness, a form of side preference with almost as long a research history as handedness. Each side preference has a signature behavior. For handedness, it is the hand used to write. For footedness, it is the foot used to kick a ball. Other behaviors that assess footedness include the foot used to stamp on a lighted match, the foot used to write one’s name in the sand, and the foot used to pick up an item with the toes. Like handedness tasks, these are behaviors requiring the use of only one limb. Typically, a person uses the same foot repeatedly to perform each of these activities
We have learned a lot about side preferences in recent years from meta-analyses of the published literature. These are helpful because the published literature on side preferences is vast and extends back into the 19th century. A meta-analysis looks at multiple published papers and organizes the results according to a set of established statistical and methodological procedures. Researchers can summarize hundreds of research findings using these techniques to give us a picture of the major results from many studies.
A recent paper reported on a meta-analysis of research on footedness.¹ This study examined data from over 150 research papers measuring collectively more than 120,000 participants. The meta-analytic results provided data on the prevalence of left- and right-footedness and the relationship of footedness to the side of the preferred hand. Overall, 16% of those tested were left-footed; they used the left foot consistently to perform tasks such as those described above. There was a higher rate of left-footedness among males when compared to females (19% versus 14%, respectively). This finding is similar to handedness results showing higher percentages of left-handedness among males. Most left-handers (66%) are also left-footed as compared to only 6% of right-handers. The majority of both left- and right-handers display handedness and footedness on the same side of the body. These recent findings are similar to data reported in my 2016 book Laterality: Exploring the enigma of left-handedness. At that time, I reported an overall rate of left-footedness of 15% with males (17%) being more likely to be left-footed than females (12%). Sixty-one percent (61%) of left-handers also showed left-footedness as compared to only 4% of right-handers. Both the meta-analytic data and my data show a 5% rate difference in left-footedness favoring males and a low incidence of left-footedness among right-handers. Both data sources indicate that the majority of left-handers are also left-footed.
Like handedness, footedness represents a movement asymmetry. One limb is preferred consistently over the other when certain tasks are performed. Researchers have suggested that footedness represents an unaltered form of limb preference because it is not subject to the training and cultural influences affecting hand preference. For example, certain cultures discourage or even forbid the use of the left hand for performing some activities. These environmental influences affect whether or not the left hand is used for everyday activities and can alter overall rates of left-handedness within a specific culture or country. Although athletes in various sports may train themselves on footedness tasks, most individuals do not actively practice in this way nor do cultures have sanctions attached to left foot use. The study of footedness in individuals has value for researchers interested in the development and genetic origins of movement asymmetries in humans.
¹Packheiser, J. Schmitz, J., Berretz, G., Carey, D.P., Paracchini, S., Papadatou-Pastou, M., & Ocklenburg, S. (2020). Four meta-analyses across 164 studies on atypical footedness prevalence and its relation to handedness. Scientific Reports, 10, 14501. https://doi.org/10.1038/s41598-020-71478-w.