Consider the bi-modal clapping that routinely rewards a successful performances—music, drama, circus, etc.—in eastern European communities, but which is less common in western Europe and North America. Z. Néda and colleagues (2000) have investigated this phenomenon, recording applause for a number of performances in Romania and Hungary. The applause would start out randomly and then quickly become strongly synchronized. Synchronized clapping would continue for a short while (one mode) and then disintegrate into random clapping (the other mode), from which synchronized clapping would reemerge, and so forth.
He also emphasises the importance of, and the need for, description in cultural evolution, drawing on Darwin's own situation in the 19th Century:
Consider the situation of Darwin faced in the 19th century. When he began formulating his ideas on the origin of species he had three bodies of knowledge to work from: prior thought on the topic, his own observations over three decades, and the cumulative results of four centuries of descriptive work in natural history (cf. Ogilvie 2006) to which he had access through books and collections. That descriptive work provided models for his own observation and description. Plants and animals, and their lifeways, are very complex. Which traits and features are the most important to observe and describe? That is not an obvious matter, and it took naturalists decades to arrive the useful descriptive methods (cf. Foucault 1973, pp. 128 ff.). Secondly, it gave him the means to abstract and generalize from his own observations, to explore their implications throughout the natural world, most of which, of course, was beyond his immediate experience.
I'm planning on posting a comment tomorrow, but only if I've got something worth adding to the discussion. I think there are definitely areas worth looking at, such as the use of phylogenetic techniques in investigating culture, though I'm still juggling in my head whether they are entirely relevant to the conversation at hand. Also, be sure to check out John Wilkins' comment about memes.