Chapter 15 Norms and Trust Rino Falcone, Cristiano Castelfranchi, Henrique Lopes Cardoso, Andrew Jones, and Eugénio Oliveira 15.1 Introduction In this chapter we would like to show how interesting and not at all trivial and obvious are the relationships between Norms and Trust. In fact, the relationship between Trust and Social and Legal Norms is rather complicated (for an analysis see also Part VI in this book). This has been object of several misunderstandings and controversies in the literature, and never clearly systematized in its various, well characterized aspects, on the basis of a principled and precise model, able to explain, not just to describe, those relationships. In this chapter we will briefly introduce some different (and in part comple- mentary) analyses and approaches to the study of this relationship. In Falcone and Castelfranchi’s contribution (see Sect. 15.2), how we can consider Trust as based on Norms (on the norm-based behavior of other agents) is analized, and, at the same time, how we can consider Norms as based on Trust, on the fact that without Trust, Norms are in practice ineffective and superfluous. In Lopes Cardoso and Oliveira’s contribution (see Sect. 15.3), starting from the fact that an agent’s trustworthiness can be evaluated on its compliance with norms, the authors consider the different ways to comply with a norm and the relationships with this analysis and the trust models. In particular the feedback on the norm adaptation. In Jones’ R. Falcone () • C. Castelfranchi Institute of Cognitive Sciences and Technologies – National Research Council, Rome, Italy e-mail: rino.falcone@istc.cnr.it; cristiano.castelfranchi@istc.cnr.it H. Lopes Cardoso • E. Oliveira LIACC/DEI, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal e-mail: hlc@fe.up.pt,eco@fe.up.pt A. Jones Department of Informatics, King’s College London, London, UK e-mail: andrewji.jones@kcl.ac.uk S. Ossowski (ed.), Agreement Technologies, Law, Governance and Technology Series 8, DOI 10.1007/978-94-007-5583-3__15, © Springer Science+Business Media Dordrecht 2013 221