Body-based measurements may have persisted because they are convenient and offer ergonomic advantages over standardized units. From a report: Although standardized units are often upheld as superior to informal corporeal measures, people in many societies have continued to use their bodies this way well after standardization has taken root, notes Roope Kaaronen, a cognitive scientist who studies cultural evolution at the University of Helsinki. To explore how widespread such practices have been in human history, Kaaronen and colleagues pored over ethnographic data from 186 past and present cultures across the world, looking for descriptions of body-based units of measurement in a database called the Human Relations Area Files. This database is the product of an international nonprofit organization that has been collecting and administering ethnographies and anthropological literature since the 1950s.
The team found these systems used in every culture they looked at, particularly in the construction of clothes and technologies. For example, in the early 1900s, the Karelian people, a group indigenous to Northern Europe, traditionally designed skis to be a fathom plus six hand spans long. In the late 1800s the Yup’ik people from the Alaskan coast recorded building kayaks that were 2.5 fathoms long plus a cockpit, which was the length of an arm with a closed fist. Next, the team looked at a subsample of 99 cultures that, according to a widely used benchmark in anthropology, developed relatively independently of one another. Fathoms, hand spans, and cubits were the most common body-based measurements, each popping up in about 40% of these cultures. Different societies likely developed and incorporated such units because they were especially convenient for tackling important everyday tasks, the authors argue, such as measuring clothes, designing tools and weapons, and building boats and structures.