"Steven Johnson: Where good ideas come from | Video on TED.com"
Contrary to the myth of the solitary inventor, Johnson finds that the great bulk of culturally significant ideas emerge in environments where people gather, talking and freely exchanging their thoughts.
Now look at this paper by Hugo Mercier and Dan Sperber ("Why do humans reason? Arguments for an argumentative theory" -- http://www.dan.sperber.fr/wp-content/uploads/2009/10/MercierSperberWhydohuman... ) :
"Reasoning is generally seen as a means to improve knowledge and make better decisions. However, much evidence shows that reasoning often leads to epistemic distortions and poor decisions. This suggests that the function of reasoning should be rethought. Our hypothesis is that the function of reasoning is argumentative. It is to devise and evaluate arguments intended to persuade. Reasoning so conceived is adaptive given humans’ exceptional dependence on communication and vulnerability to misinformation. A wide range of evidence in the psychology of reasoning and decision making can be reinterpreted and better explained in the light of this hypothesis."
And check out Bill Benzon's post about "copycats": "Copycats are us" http://new-savanna.blogspot.com/2010/09/copycats-are-us.html
I think I see the beginnings of an ecology of thought and culture.