by F.A. Hayek
Hayek's definition of cultural evolution, which can be found in "The Fatal Conceit - The Errors of Socialism" 
Buy it! is surprisingly closely related to Dawkins' definition of the evolution of memes. I had to look at the book's bibliography to see if Hayek had been inspired by Dawkins (The Fatal Conceit was written in 1989) but although many biology authors are cited, there is no mention of Dawkins in the bibliography.
In the first chapter, entitled "Between Instinct and Reason", Hayek points out many similarities between cultural evolution and genetic evolution. Hayek seems to struggle at finding a classification for cultural evolution, which he sees as being neither natural, which he defines as phenomena that limit themselves to genetics, nor un-natural, phenomena that are brought about through reason and mindful design.
"The similarity of the order of human interaction to that of biological organisms has of course often been noticed. But so long as we were unable to explain how the orderly structures of nature were formed, as long as we lacked an account of evolutionary selection, the analogies percieved were of limited help. With evolutionary selection, however, we are now supplied with a key to a general understanding of the formation of order in life, mind, and interpersonal relations." (p.144)
Hayek classifies cultural evolution to be between instinct (genetics) and reason (intellect), not unlike memes, which Dawkins describes as a new form of replicators operating independently from both genes and intellect.
Hayek points out that it is outside mankind's intellectual ability to determine the course of cultural evolution, including the evolution of our societies, economies, customs, and traditions. The idea that man is able to shape his cultural evolution according to his wishes and plans is what Hayek calls the Fatal Conceit.
Hayek uses this insight to explain how the concepts (memes) of free markets and trade have evolved over time independently of anyone's particular planning or design. Although he doesn't use this terminology (he calls it the "extended order"), Hayek explains how individual humans have carried these memes through time and civilisations simply by going along with their selfish businesses, without really being aware of the meme's incredible achievements (trade and markets) and importance to the survival of civilisations.
I recommend "The Fatal Conceit" to anyone who has an interest in memetics, politics, and economics.
See Also: FriedrichHayek