[InfernoLL]

The division of labor is only a cooperative structure in very small "band" or "tribal" societies. In any modern society of any size, the division of labor is achieved entirely through competition.

Referring to "society" as a cooperative structure is also suspect. You haven't defined "society" so this doesn't really mean anything. If you include the economy in your definition of society, then it cannot be a fundamentally "cooperative structure". If you mean "government" then cooperation only plays a partial role; while law makers must work together, they must also represent the competing views of their constituencies.

"In fact cooperation is one of the key factors which distinguishes humans from lesser species."

This is a pretty ridiculous statement. Ever seen a flock of birds or a school of fish or a pride of lions or a bee hive? I think the best example of cooperation on earth is a group of insects like an ant hill or a bee hive or a termite mound, etc. The actual key factor that distinguishes humans from lesser species is intelligence, which happens to manifest itself in things like language, advanced problem solving, and abstract conceptualization.

"And the research evidence seems to indicate that increasing cooperation rather than competition leads to higher performance."

While I don't read psychology journals or anything like that, it would seem that this result you've stated could be very misleading. I would very readily believe that increased cooperation would benefit those in the lower portion of the continuum, and that competition would hurt them. But this doesn't contradict anything anyone's saying. The purpose of competition is to make the best better, and to force others to earn what they get. I don't think it's likely that the smartest kid in the class is going to benefit from a system whereby he is not able to both demonstrate that he is the smartest and be rewarded for it.