This paper explores issues of versification as an epitome of culural programs. It is devoted to the question of how cognitive processes shape and constrain cultural and literary forms. It assumes that the generation of culture is governed by adaptation devices exploited for cultural and aesthetic ends. The argument is propounded in four stages. The first stage deals with an issue of poetic prosody, foregrounding the conflict between the influence-hunting and the cognitive-constraint approaches to the same problem. The second stage adduces an instance of how "in the process of repeated social transmission, cultural programs come to take forms which have a good fit to the natural capacities of the human brain." The third stage treats the versification systems as cultural artifacts and attempts to account for the differences between them. The fourth stage examines what appears a counterexample to one of the central generalisations in this paper. The concluding section not only summarizes the paper's arguement, but also widens its scope, briefly alluding to some further research, in which similar cognitive assumptions are applied to an instance of figurative language: the metaphysical conceit. [R.T.]