This paper looks into how two main frameworks view the acquisition of syntax. These are the nativist approach which claims that language is acquired because human beings are equipped with a language acquisition device in the form of grammatical knowledge, and the cognitivist approach which views language like the other cognitive skills and so claims that we acquire language using general cognitive mechanisms that are not specific to language. The paper reviews a number of studies that report on the acquisition of various aspects of the syntax of natural language; the studies are from both frameworks. The paper then evaluates the claims of the reviewed studies in light of the respective findings, as well as in light of how the findings may be interpreted by the other framework. The paper also presents an analysis of the argumentation techniques that the respective authors use, as well as of how effective they are. It concludes with a proposal for a line of research which is based on research techniques and findings in second language acquisition.