["Nudges": relevance, limitations and ethical issues, specifically in health policy].

The concept of "nudge" has recently spread accross the field of research that addresses the issue of health behaviours change. According to Thaler and Sunstein (2008) a nudge is "any aspect of the choice architecture that alters people's behavior in a predictable way without forbidding any options or significantly changing their economic incentives". Similar concepts, such as persuasive technology or manipulation, have been studied for decades in the fields of design, psychology or communication. The novelty of the concept of "nudge"' lies in its particular political purpose, namely libertarian paternalism. Meanwhile, the analysis of the decision process induced by a nudge shows that it does not simply amount to a change in the environment and that its handling is ethically tricky. The main interest of this concept might actually lie in a better assessment and a better regulation of the public health impact of choice architecture for economic purposes, such as marketing and advertising.