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(Comparative Anatomy and Physiology Brought Up to Date--continued, Part 3C)

Diet, Evolution, and Culture

Feedback loop between evolution and culture

As discussed above, those aspects of culture that are universal, or nearly universal (tool use, meat-eating, and after the discovery and regular use of fire, eating cooked food) can and will impact evolutionary selection pressure. It does not matter whether such behavior is absolutely required for survival in any possible imaginable circumstances. What counts is that such behavior is universal (or nearly so) and therefore effectively required for survival under the actual conditions (which necessarily includes behavioral conditions) that a given individual or species finds itself. Thus there is an important feedback loop between evolution and behavior (culture).

For another perspective on this, note that humans are unique because of their high intelligence (discussed in the next section). Given such intelligence, human survival becomes a function of behavior. And because of our high intelligence, human behavior (which constitutes part of the ongoing evolutionary environment) can be a malleable choice rather than a compelling "instinct." Further, behavior can be, and is, a part of culture. (Culture can be seen as a set of group-specific behaviors that are acquired via social means; see McGrew [1998] for discussion.)

The following figure illustrates the nature of the behavior/culture evolutionary feedback loop. It is a modification of fig. 29.1, p. 439, from Wood [1995].

FLOWCHART: Behavior/culture evolutionary feedback loop.

Courtesy link to Yale University Press graciously provided
in exchange for permission to reproduce the above figure.

Diet and early social organization

Spuhler [1959] comments on the likely interaction of diet and culture (pp. 6-7):

The change to a partially carnivorous diet had extremely broad implications for the social organization of early hominoids. [Note: "hominoids" (includes great apes and humans as a class) is probably a typo in the original here; "hominids" (which means humans and their bipedal predecessors) is likely what is meant.] Carnivores get a large supply of calories at each kill. This concentrated food is more easily transported to a central, continually used shelter than is low-calorie plant food, especially before containers were available...

Compact animal protein high in calories is a good basis for food sharing...It is unlikely that the long dependency of human children--so important in the acquisition of culture by individuals--could develop in a society without food sharing. And the amount of information which needs to be transduced in a communication system for plant eaters like the gibbons is small compared to that needed in group-hunting of large animals.

Did the human brain give rise to culture and tool use, or vice versa? Washburn [1959] considers the relationship between tool use and biological evolution, and observes (pp. 21, 29):

[M]uch of what we think of as human evolved long after the use of tools. It is probably more correct to think of much of our structure as the result of culture than it is to think of men anatomically like ourselves slowly discovering culture...

The general pattern of the human brain is very similar to that of ape or monkey. Its uniqueness lies in its large size and in the particular areas which are enlarged. From the immediate point of view, this human brain makes culture possible. From the evolutionary point of view, it is culture which creates the human brain.

The remarks of Spuhler and Washburn illuminate the culture-evolution feedback loop. The argument that "meat-eating does not (directly) impact the reproduction of individuals, hence we are not adapted," is erroneous because it ignores this important feedback loop.

Evidence of dietary culture in non-human primates

Some fruitarian extremists are quick to condemn all (human) cultural dietary habits as being allegedly unnatural. However, non-human primates show evidence of rudimentary, dietary cultural habits. Nishida [1991, p. 196] notes:

Humans display diversified food culture: E. Rozin (1973, cited by P. Rozin, 1977) called "cuisine" culturally transmitted food practices...

Nonhuman primate species also display diversified food habits within their own geographic distribution...

The most easily observable result of cultural transmission processes is the difference in modes of behavior between different local populations of a species, which is uncorrelated with gene or resource distribution (Galef, 1976).

Nishida [1991] provides an impressive listing of the differences in feeding behavior of chimpanzees, baboons, and monkeys. Of possible interest to raw-fooders is his description of the macaques of Koshima Island, Japan dipping food into seawater for seasoning (some raw-food advocates stridently condemn the practice of seasoning foods). Of course, that non-human primates display cultural food preferences suggests human cultural food preferences are an extension of that feature.

There is an extensive body of scientific research on the topic of culture in non-human primates. For two recent papers that provide an entry to the research, consult McGrew [1998], which discusses culture in several non-human primates, and Boesch and Tomasello [1998], which compares chimpanzee and human cultures.

Fruitarian Extremists Retreat into Creationism

As the general information that the evolutionary diet (actually, range of diets) of humans included animal foods has spread into the raw vegan community, certain fruitarian extremists who want to continue to propagate the myth that 100% raw vegan/75+% fruit diets are the "most natural" diets for humans have made a hasty retreat into what could be called secular creationism. (This is similar to the sudden appearance of claims that the mountain gorilla is "closest" to humans, and vegan.) Relevant observations here are:

Adaptation in Action:
Fruitarian Reaction to New Information

It is interesting to observe that certain fruitarian extremists--after their claims that "chimps are vegans" and "we evolved on a purely fruit/vegan diet" were discredited--adapted very quickly. In a matter of months (less than a year) new myths evolved and were promoted: "Humans are just like vegan mountain gorillas" plus the idea that species are created (nature is a "mystery") rather than evolved.

Thus we can wryly observe that certain fruitarian extremists "adapted," in less than a year, to the debunking of their old mythology with a brand-new mythology. And yet these same folks claim that humans cannot and did not adapt, via evolution, over ~2.5 million years, to a diet that includes some meat. Admittedly, these are different adaptations--one intellectual, the other physical. But we see that intellectual "adaptation" can be very rapid indeed, and the contrast between rapid intellectual adaptation versus claims that physical adaptation absolutely CANNOT have occurred in ~2.5 million years (despite fossil record evidence of physical change) presents us with an example of "raw irony"--a not-uncommon feature of the more extreme wing of the raw vegan movement.

Ironic, contradictory views of "nature's laws"

To add further irony to the situation, some fruitarian extremists simultaneously claim both that:

Of course, the ability of fruitarian extremists to contradict themselves so clearly, and get away with it, rests on the gullibility and idealism of their followers. This is yet another example of "raw irony," though in this case a much more unfortunate one (for the followers).

To Summarize:


(Intelligence, Evolution of the Human Brain, and Diet)

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GO TO PART 1 - Brief Overview: What is the Relevance of Comparative Anatomical and Physiological "Proofs"?

GO TO PART 2 - Looking at Ape Diets: Myths, Realities, and Rationalizations

GO TO PART 3 - The Fossil-Record Evidence about Human Diet

GO TO PART 4 - Intelligence, Evolution of the Human Brain, and Diet

GO TO PART 5 - Limitations on Comparative Dietary Proofs

GO TO PART 6 - What Comparative Anatomy Does and Doesn't Tell Us about Human Diet

GO TO PART 7 - Insights about Human Nutrition & Digestion from Comparative Physiology

GO TO PART 8 - Further Issues in the Debate over Omnivorous vs. Vegetarian Diets

GO TO PART 9 - Conclusions: The End, or The Beginning of a New Approach to Your Diet?

Back to Research-Based Appraisals of Alternative Diet Lore

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