This article presents the subset of research on the enhancement of cooperation in negotiation with a focus on the intraorganizational context. It studies the long‐term effect of negotiation training and its implications for the teaching of negotiation. We chose a qualitative approach over two cycles of action research. Cycle 1 was performed in a training course with sixty‐four managers over six months. Cycle 2, using the focus group method, was carried out with eleven individuals selected from cycle 1 population over twelve months. This experiment enabled us to propose a dynamic typology of negotiator styles, which led us to suggest a number of recommendations to improve the teaching of negotiation.