Number Lines Not Innate

A publication in the past week in PLoS (Núñez, Rafael, Kensy Cooperrider, and Jürg Wassmann. “Number Concepts Without Number Lines in an Indigenous Group of Papua New Guinea.” PLoS ONE 7, no. 4 (April 25, 2012): e35662. http://dx.doi.org/10.1371/journal.pone.0035662) offers some interesting new data that relates to the origin of timelines. In essence, Núñez and his fellow researchers have found a people in New Guinea who do not arrange numerical quantities in a strictly calibrated way along a line because they do not actually work with a mental number line. There is a news release by Inga Kiderra too.

A more readable account of the ideas behind the research can be found in an article published last year: Núñez, Rafael. “No Innate Number Line in the Human Brain.” Journal of Cross-Cultural Psychology 7 (2011): 651. http://www.cogsci.ucsd.edu/~nunez/web/Nunez_JCCP11.pdf.

This is highly suggestive of the environment in which the Great Stemma was written, and circles were arranged in approximate fashion in left-right space without being calibrated to a scale. Núñez argues that conceptual mappings onto space are culturally and historically determined and rejects the nativist hypothesis that they are hard-wired into the human brain.

My hypothesis is that the 5th-century Latin author of the Great Stemma mapped time onto the space of a long papyrus roll, but felt no compulsion to finely calibrate it as a number line. We have an author with a high classical education who is comparable to the Yupno people with grade-school education that Núñez and his fellow researchers encountered in New Guinea. Both the author and the Yupno are carrying out mapping operations, but have not yet entered a cultural environment where they are obliged to do this in a strict way on pain of being labelled uneducated if they do not.