Stone-Age Internet

October 27, 2011

One thing that serves to distinguish man from other species is his use of tools. At one time, it was believed that only man was a tool user, but there are numerous examples of tool use in other species.

Man's first use of stone as a tool started in the Lower Paleolithic, about 2.5 million years ago. The Lower Paleolithic was the start of the Stone-Age. This age of man in which stone was the sole tool continued up until 5,000 years ago. At that time, metallurgy of copper and its alloy, bronze, was developed, ushering in the Bronze Age.

A horse of a different color. Paleolithic rock drawing, from Theo van Doesburg, "Drie Voordrachten over de Nieuwe Beeldende Kunst Verscheen," 1919, p. 65 (Via Wikimedia Commons).

Other traits that distinguish man are his sociability and use of language. Communication of ideas in the Stone Age was mostly by demonstration, including primitive images that may have conveyed some information (see image above). There is conjecture that language developed in the Middle Stone Age. In any case, physical contact between individuals was necessary to convey information.

Modern human behavior, such as development of complex symbolism and technologies, started to show in our Stone Age ancestors about 45,000 years ago. A 2009 paper by Adam Powell, Stephen Shennan and Mark G. Thomas offered evidence that population density and migratory patterns were responsible for this change, not any increased cognitive capacity.[1] The extended population allowed a stable information flow throughout the human populace so that, in effect, everybody didn't need to keep reinventing the wheel.

When a physicist reads something like that, he realizes that what's proposed is a percolation model for diffusion of information. The evidence for a sharp phase transition from dumb brute to cave painter is further evidence that percolation is a reasonable model.

An image of a horse from the Lascaux caves. The Lascaux painting are estimated to be about 17,300 years old, which places them in the Upper Paleolithic. (Via Wikimedia Commons).

In a simple two-dimensional percolation model, the plane is divided into a checkerboard of cells. Agents can randomly populate these cells, and they can be constrained to communicate only with agents on adjacent cells. It's fairly obvious that a small density of agents doesn't allow the possibility of communication from one corner of the plane to another. However, at a critical density, information flow from one side of the plane to the opposite side is allowed.

Such a percolation model for information diffusion in the Stone Age was examined in a recent posting on the arXiv Preprint Server by four Palestinian physicists, M.A. Sumour, M.A. Radwan, M.M. Shabat and Ali H. El-Astal.[2] In the case of Stone Age communication, the checkerboard is populated by campsites of small human groups. The cells are separated by a reasonable distance for casual communication, about a day's walk, or two.

Romanticized vision of a Stone Age family around a campfire. (From "The Cave Boy of the Age of Stone," by Margaret A. McIntyre).[3]

Since the standard percolation model is just concerned with the connections between cells, the research team incorporated the idea that there must be enough time for information to travel from one group to another by assuming that the data has a lifetime. In the mechanics of a percolation computation, this would be a limit on the number of iterations in the model.[2]

In a standard percolation model, only 0.593 of the cells need to be filled to allow connection from one corner to another. The results in the arXiv paper show that adding the additional constraint of the lifetime of information means that the filled fraction of cells needs to be much larger. Stone Age civilization would only blossom when the human population was quite large.[2]

One factor that might reduce the required cell occupancy is the idea that humans do not stay in a single place, but they tend to move about. Such movement, which the arXiv authors characterize as annealed, rather than quenched disorder, might facilitate information transfer.[2]

References:

1. Adam Powell, Stephen Shennan and Mark G. Thomas, "Late Pleistocene Demography and the Appearance of Modern Human Behavior," Science, vol. 324, no. 5932 (June 5, 2009), pp. 1298-1301.
2. M.A. Sumour, M.A. Radwan, M.M. Shabat, Ali H. El-Astal, "Statistical physics applied to stone-age civilization," arXiv Preprint Server, October 13, 2011.
3. Margaret A. McIntyre, "The Cave Boy Of The Age Of Stone," Harrap (London, Not Dated, Certified Public Domain by Archive.org).