In writing this title, I realized that it may become unintelligible to future generations. As digital clocks replace analog ones, we may need a better term altogether. Mathematics, of course, does not depend on clocks to define the direction around a circle; what we call anticlockwise is simply the positive direction.
What spurred this post was an article I came across in which one of the co-authors was K. Nishinari. I have known Nishinari-san for many years. I have visited and lectured in his laboratory at the University of Tokyo, and we even once planned a collaboration (which, unfortunately, never materialized). He describes himself as a “jamologist,” a specialist in “jams” — traffic jams, but not only. I still remember one of his seminars, in which he explained how to avoid jams in inkjet printers. I had to follow the seminar in Japanese, a language I do not speak, yet I managed to understand the topic thanks to Nishinari-san’s excellent presentation.
This time, the question was whether there is a left-right symmetry breaking when we move in crowds. In other words, do we tend to favor clockwise or anticlockwise turns? (Perhaps I should point out to my American readers that what I call anticlockwise is what they would call counterclockwise). The article, based on a Spanish-Japanese collaboration, was published in Nature Communications. The authors found that an anticlockwise bias in roaming pedestrians is a robust and reproducible feature. It is independent of crowd size, boundary effects, laterality traits (handedness, footedness, or eye dominance), and social norms. (Admittedly, the study participants were children and young adults, which raises the question of what would happen in the case of individuals with functional limitations). More importantly, the authors showed that the anticlockwise preference originates in individual locomotor tendencies rather than in collective interactions. (This runs counter to the common belief that group-level behaviours are more than the sum of individual behaviours).
The authors do not offer an explanation for this phenomenon, but they do mention some preliminary studies of blindfolded walking, which resulted in a circular motion in one direction “due to accumulating drift in their subjective straight-ahead, possibly linked to vestibular noise”. I will not delve further into this excellent article from the Spain-Japan collaboration. If you are interested, you can find it here.
Back to the anticlockwise preference. If you are, like myself, a swimmer who has to share a training lane with more than one other swimmer, thereby requiring everyone to adopt a circulation that keeps the dividing line always on the same side of the body, it seems natural that the resulting circular motion should be anticlockwise. I cannot claim that this is a spontaneous choice: it may well be a learned behaviour. Still, I have never seen anyone turn clockwise in a swimming lane.
But let us start at the beginning. As always, we have no technical details concerning ancient Athletics. The Ancient Olympics began with the στάδιον (stadion), a run from one end of the stadium to the other. Soon, the δίαυλος (diaulos) was introduced, in which one had to run to the end of the stadium and back. Unfortunately, nothing is known about how the athletes made their turn. On the other hand, literature does exist concerning ancient chariot and horse races, and there it is clear that in the ancient Hippodrome the races proceeded anticlockwise. (I once read a curious story according to which, during Roman times, chariot races in the Circus Maximus were initially run clockwise and later changed by an edict of Nero, after he was struck by the whip of a charioteer. But I would not attach much credibility to that account).
The ancient Greek tradition did not survive into the revival of modern sport. When athletics re-emerged in the nineteenth century, clockwise running was still common, and Oxford and Cambridge are reported to have practiced it well into the twentieth century (which is hard to reconcile with the fact that the direction became standardized soon after the London Olympics of 1908). At the first modern Olympic Games in Athens in 1896, track races were run clockwise; the same was true in Paris in 1900 and St. Louis in 1904. A short video from the 1906 Athens Olympics survives, but it shows only the 110 m hurdles; even so, the layout of the track and the direction of the race suggest that clockwise running was still in place at that time. By then, however, several countries had already adopted the anticlockwise convention, and complaints were being voiced. In London, athletes therefore ran with 'the left hand inside', and some sources even mention an IOC decision in 1913 to formalize anticlockwise running. That attribution is somewhat puzzling, since the International Amateur Athletic Federation had already been founded in 1912 and was the body normally responsible for technical matters. In any case, anticlockwise track running has now been the standard for more than a century, and it is unlikely to change anytime soon. And the article by Nishinari et al. provides a scientific rationale for a convention that may once have seemed purely arbitrary.
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