Journal article: In economics, three nested organizational levels, namely behavioural, mental and neural, can be distinguished. They introduce specific theoretical or observable concepts and suggest their own models for choice making. If psycho-economics relates implemented actions to declared mental states, neuro-economics relates mental states to brain areas. Bridge principles can be defined which link concepts with similar interpretations at two successive levels. Thanks to these principles, relations or even models independently suggested at two successive levels may well be associated. Some prescriptive applications of these principles were more recently proposed, but they remain grounded on a too fragile basis.