This study focuses on the cognitive processes involved in creole genesis: relexification, reanalysis, and direct leveling. The role of these processes is documented by a detailed comparison of Haitian creole with its two major contributing languages, French and Fongbe, to illustrate how mechanisms from source languages show themselves in creole. The author examines the input of adult, as opposed to child, speakers and resolves the problems in the three main approaches, universalist, superstratist and substratist, which have been central to the recent debate on creole development.