There is now ample evidence that jobs and wages have been polarizing at the extremes of the skill distribution since the early 90s. Autor, Levy and Murnane (2003) have suggested that this might be due to technology substituting more easily for labor in performing routine rather than non-routine tasks. Other potential explanations include globalization. Active empirical research has now identified ... [Show full abstract] important stylized facts. The aim of this paper is to provide a theoretical exploration of alternative potential causes to this labor market polarization, and to identify which, if any, are consistent with the stylized facts.. <Jung@wiwi.rwth-aachen.de>. ERMES, Université Panthéon-Assas (Paris 2), <Jean.Mercenier@u-paris2.fr>. We are grateful to Maarten Goos, Thomas Lemieux and Gerald Willmann for encouragements. We also wish to thank participants at the BIBB-IAB TASKS Workshop (Nürnberg May 2010) for comments.