Part Of: Culture sequence
Excerpt From: Henrich (2015). Secret of Our Success
Content Summary: 1000 words, 5 min read
The loss of adaptive cultural information can result from two different processes. The first is what we saw happen to the Polar Inuit: a random shock (an epidemic) happened to strike the most knowledgeable members of the community, wiping out a chunk of their cultural know-how. Because it removed the kayak (their transportation) from their cultural repertoire and they were already geographically very isolated, they went into a slow downward spiral as their populations dwindled due to the technological losses. This kind of phenomena may be common.
The other process is more subtle and I suspect more important. If someone is copying the techniques and practices of a highly skilled and knowledgeable expert, they will often end up with a level of skill or knowledge that is less than that of the expert they are copying. The reason is that some information was lost every generation, because copies are usually worse than the originals. Cumulative cultural evolution has to fight against this force and it is best able to do so in larger populations that are highly socially interconnected. The key is that most individuals end up worse than the models they are learning from. However, some few individuals, whether by luck, fierce practice, or intentional invention, end up better than their teachers.
Larger populations can overcome the inherent loss of information in cultural transmission because if more individuals are trying to learn something, there’s a better chance that someone will end up with knowledge or skills that are at least as good as, or better than, those of the model they are learning from. Interconnectedness is important because it means more individuals have a chance to access the most skilled or successful models, and thereby have a chance to exceed them.
The Tasmanian Effect
These ideas first struck me when I was reading about the aboriginal inhabitants of the island of Tasmania. Roughly four-fifths the size of Ireland and comparable to Sri Lanka, Tasmania lies about 200 kilometers south of Victoria, Australia. When the earliest European explorers made contact with the Tasmanians in the late eighteenth century, they discovered a population of hunter-gatherers equipped with the simplest toolkit of any society ever encountered (by Europeans). To hunt and fight, men used only a one-piece spear, rocks, and throwing clubs. For watercraft, the Tasmanians relied on leaky reed rafts and lacked paddles. To ford rivers, women would swim the raft across, towing their husbands and offspring. In the cool maritime climate, Tasmanians slung wallaby skins over their shoulders and applied grease to their exposed skin. Curiously, the Tasmanians did not catch or eat any fish, despite fish being plentiful around the island. They drank from skulls and may even have lost the ability to make fire. In all, the Tasmanian toolkit consisted of only about twenty-four items.
To put this simplicity into perspective, let’s consider the Pama-Nyungan-speaking Aborigines who were contemporary with the Tasmanians in the eighteenth century, and lived just across the Bass Strait in Victoria. These Aborigines possessed the entire Tasmanian toolkit plus hundreds of additional specialized tools, including a fine array of bone tools, leisters, spear throwers, boomerangs, mounted adzes (for woodworking), many multipart tools, a variety of nets for birds, fish, and wallabies, sewn-bark canoes with paddles, string bags, ground-edge axes, and wooden bowls for drinking. For clothing, rather than draped wallaby skins and grease, the Aborigines wrapped themselves in snugly fitting possum-skin cloaks, sewn and tailored with bone awls and needles. For fishing, the aboriginal populations used shellfish hooks, nets, traps, and fishing spears. Somehow, the Tasmanians ended up with a much simpler toolkit than did their contemporary cousins just across the Bass Strait.
The Tasmanian toolkit is simple even when compared to that of many ancient Paleolithic societies. The archeological record from many parts of the world, going back tens and even hundreds of thousands of years, reveals the emergence of more-complex toolkits than those possessed by the Tasmanians at the time of European contact. Tasmanian stone tools are much cruder than many of the tools found in Europe made by many Neanderthals. The Tasmanians lacked bone tools, yet elsewhere finely crafted bone harpoon points date to at least 89,000 years ago. Similarly, stone points for spears date to a half a million years ago, well before the emergence of our species. Hafted tools date back before the origins of our species, 200,000 years ago.
The puzzle deepens when we realize that Tasmania was connected to the rest of Australia until about 12,000 years ago. As the seas rose, the Bass Strait flooded and transformed Tasmania from an Australian peninsula to an island. Until this isolation, the archaeological remains left by Tasmanians cannot be distinguished in terms of complexity from those found in Australia. With their isolation, Tasmanians began to lose complex tools. The number of bone tools gradually dwindled until about 3,500 years ago, when they vanished entirely. As evidenced by fish bones, at least some ancient Tasmanian groups probably relied heavily on fish. But, gradually. fish dwindle and disappear from the record. By the time Captain Cook’s men offered freshly caught fish from the bountiful waters around the island in 1777, the Tasmanians reacted with disgust; yet, they gladly took and ate the bread Cook offered.
By isolating Tasmanians for eight to ten millennia, the rising seas cut them off from the vast social networks of Australia, suddenly shrinking their collective brains (supermind). A gradual loss of their most complex and difficult to learn skills and technologies ensued.
Supermind Over Mind
In class, I show my undergraduates unlabeled pictures of four different stone toolkits from (1) eighteenth-century Tasmanians, (2) seventeenth-century Australian Aborigines, (3) Neanderthals, and (4) late Paleolithic modern-looking humans (30,000 years ago). I ask them to assess the cognitive abilities of the toolmakers by looking at the tools. My students always rate the Tasmanians and Neanderthals as less cognitively sophisticated than both the seventeenth-century Australian Aborigines and the late Paleolithic toolmakers. Of course, there’s no reason to suspect any innate cognitive differences between Tasmanians and Aborigines, who only became separate populations after the Bass Strait flooded.
Because most Neanderthal groups possess a toolkit substantially less complex than the more modern-looking African intruders (our ancestors), the assumption has often been that Neanderthals suffered some innate cognitive deficits.
In primates, the strongest predictor of cognitive abilities across species is overall brain size. Consequently, it’s not implausible that we were dumber than the bigger-brained Neanderthals. However, they had larger collective brains capable of generating greater cumulative cultural evolution.
- Gott (2002). Fire making in Tasmania: Absence of evidence is not evidence
- Henrich (2004). Demography and cultural evolution: Why adaptive cultural processes produced malapative losses in Tasmania
- Rivers “The Disappearance of Useful Arts”
- Jones (1977). The Tasmanian Paradox.
- Jones (1995). Tasmanian Archaeology: Establishing the Sequences