Before moving on in this series we need to make a correction.
One antonym for cooperation is competition; another is individualism. In the context of the behavior we have been discussing, individualism, not competition, was the appropriate term to use.
The inferences we have made are not affected but it is important to have the concept right.
Let us go over the essentials again and in a little more detail. The essence of the argument was that the nature of the labor requirements of different staple diets could be so different as to socialize very different behavioral attitudes in the communities.