 As a result, the IR discipline has been divided into two main strands: traditional or non-positivist and scientific or positivist (neo-positivist). At a later stage the third strand: post-positivism has been added. The traditionalists raise normative questions and engage with history, philosophy and law. The scientists or positivists stress a descriptive and explanatory form of inquiry, rather than a normative one. They have established a strong presence in the field. Already by the mid-1960s, the majority of American students in international relations were trained in quantitative research, game theory, and other new research techniques of the social sciences. This, along with the changing international environment, had a significant effect on the discipline. 