Positive Feedback Loops in Early Human Development

e-mail: Dan Hammer

This comic strip was taken from There's Treasure Everywhere, a collection of Calvin and Hobbes cartoons. Bill Watterson has been able to adequately describe in full the trials and tribulations of humanity using only the exploits of a six-year-old and his stuffed tiger; a genius beyond his time.

There is no doubt that technology facilitated human development throughout history. However, what has been left largely untouched among the authors of the texts for this course is why technology has had such a tremendous effect on the evolution of the human species and its relationship with its environment. This essay will attempt to show that the effects of technology were subject to a multiplier effect inherent in positive feedback loops. In other words, every historical technological innovation gave way to a change in human behavior and physical capabilities, which, in turn, allowed for further technological innovation. Because this loop has been so incredibly successful, humans have overwhelmed the environment by continually growing towards, and sometimes beyond, its natural carrying capacity. The only reason why humans have not surpassed the upper limit of environmental tolerance is our own technological innovation which exists as part of the positive feedback loop; hence the origin of the term "tech fix" (the idea that human ingenuity will overcome all environmental limitations).

The positive feedback loop that is responsible for the dominance of the human species is very much like a game of elementary school dodge-ball. Initially, there is no skill involved; a mess of children with the sole intention of remaining alive in the game. Only, it is not entirely random because there are the few children who are particularly well-suited for the game. Be it because they are more agile or perhaps they understand the movement a little better than the rest. Whatever the reason, they are able to continue playing the game longer than a child who runs around as if his eyes were closed. The more able children will then gain more experience and be able to stay in even longer and dominate in the next game, and so the positive feedback loop proceeds to take shape. Early humans were similar in that what set them apart from the rest of the animals is that, for some reason, they had a natural inclination towards tool-making and technology. With these tools they were able to dominate the evolutionary "game", so to speak. The multiplier effect comes from the fact that the loop, once it has begun, will be self-propagating, such that one invention will inevitably allow for another. Conversely, a negative feedback loop is "self-limiting rather than self-reinforcing", as put by Tom Tietenberg in his text Environmental and Natural Resource Economics. He cites James Lovelock's, an English scientist, Gaia Hypothesis which suggests that the earth is a living organism with a complex feedback system always attempting to restore chemical and physical balance in a self-regulating process. However, there is no evidence of a negative feedback system existing on a smaller scale. Early humans roamed the earth in small groups of 25-50 people about 2 million years ago (Ponting 20), which meant that they could destroy everything in their path without even leaving the slightest scratch on a global level. Negative feedback loops, it seems, only kick in when the carrying capacity for a relatively large area is exceeded, which is indicative of unsustainable growth patterns. The destructive activity, such as burning down forests as a hunting practice (Ponting), on such a small scale was sustainable because the nomadic humans left the land fallow long enough to regenerate. When these practices begin to take place on a larger scale, irreparable damage is done to the environment because there is no limiting factor. Authors such as John McCrone, in his discussion of the development of fire as a technology (McCrone 30) fails to adequately consider the second part of the feedback loop: the effect that fire had on the evolution of the human species. He is concerned mostly with how the evolution of humanity allowed for the development of fire, but does not necessarily touch upon how fire may have furthered human development.

Repercussions of a single human invention cannot be quantified because of the multiplier effect. It is possible, though, to examine the immediate benefits that come as a result and how those newfound luxuries helped in furthering the feedback loop. An example is the bow and arrow which is estimated to have come into use 23,000 years ago in Europe (Ponting 29). As an alternative to the spear (which in and of itself was a major technological feat), the bow and arrow was much less manpower intensive because of its increased range, power, and accuracy. It also allowed for man to take out the strongest of the heard rather than the old and weak, which means more meat with less effort. The time that would have been spent hunting in a less efficient system could now be used for the further development of culture and technology. The bow and arrow also meant that a tribe of hunter-gatherers could now support a greater number. This example is only one step of a virtually infinite cycle of human evolution. Another development that came into existence at around the same time and place was warmer clothing as a result of the eyed-needle. Hoods, mittens, and coats that could now be made of heavier insulating materials allowed for inhabitants of Europe to withstand the harsh cold. Ponting describes the magnitude of the invention in his text as follows:

"Good insulation from the cold provided by warm clothing meant that the level of calorie intake necessary in the harsh conditions was kept low enough to be extracted from the environment…"

Early Europeans could now support a larger population in addition to having more time for other activities as mentioned in the following:

"The development of new [survival] techniques was probably accompanied by a greater degree of specialization within gathering, hunting, and herding groups and the use of increasingly high quality materials that could only be found in a small number of locations led to the creation of regional networks for their exchange." (Ponting 29)

Not only did the new technology, in this case a technique, have major evolutionary implications as humans were able to survive in entirely new environments, but it also had a profound impact on the development of modern human culture.

Approximately 50,000 years ago, humans arrived on the continent of Australia from
An example of a positive feedback loop that eventually failed was that which took place on the infamous Easter Island. The island was originally colonized by Polynesian explorers in the fifth century (Ponting 2). The carrying capacity of the island when it was found probably could not have supported an advanced civilization, but the settlers brought with them a somber agriculture that revolved around the cultivation of yams. This allowed the island to support many more people than it otherwise would have and even allowed for the leisure time necessary for further technological innovation. However, beyond this point, the feedback loop failed for the population on Easter Island when they were not able to find anyway to further push back the carrying capacity of the island. The islanders expanded and practiced unsustainable practices until all of the island's natural resources were depleted way beyond the island's natural carrying capacity. By 1722, when the first European visited the island, its society had diminished to a people of perpetual warfare in complete disrepair, a far cry from the grand civilization that had once flourished on the island. The fact still remains, however, that for some time the human positive feedback loop allowed for human domination over its environs.

Julian Simon was a well-known population economist who has a great deal of faith in the human positive feedback loop always being able to extend the carrying capacity of our environment. Simon's The Ultimate Resource claims that human ingenuity will be able to overcome any degree of natural resource scarcity or threshold we can encounter:

"The ultimate resource is people - skilled, spirited, and hopeful people who will exert their wills and imaginations for their own benefit, and so, inevitably, for the benefit of us all."

This is quite the statement coming from a discipline based on the premise that nothing is infinite given that there is always a degree of scarcity. Perhaps humanity will overcome scarcity in the environment with some amazing feat of engineering, but as of now, it looks as if the current feedback loop is growing without bound and putting ever more pressure on the carrying capacity of our ecosystem.

Works Cited:

"Fired Up," McCrone, John; New Scientist 05/20/00, Vol. 166, Issue 2239, pp. 30-34.

Ponting, Clive. A Green History of the World: The Environment and the Collapse of Great Civilizations. St. Martin's Press, New York, 1991. ISBN 0-312-06989-1, McCabe GF75.P66 1992 pp. 1-67.

Tietenberg, Thomas. Environmental and Natural Resource Economics. Addison Wesley, New York, 2003. ISBN 0-201-77027-X, pp. 7-11.

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last updated 2/13/02