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					Originally Posted by Undertoad  Our cultural differences APPEAR to be genetic, because they happen over so many generations of time that we can't see where the changes happened. | 
	
 Hence the idea of "memes" evolving similarly to genetic evolution, and for the same reason - cultural groups are separated mentally like evolutionary groups are separated geographically, with some mixing along the borders, and imperfect duplication and a changing environment causing change over time.