Le società che, più di altre, sono state in grado di costruire e sviluppare norme e legami fiduciari, dalla condivisione di cibo tra i cacciatori-raccoglitori fino alle transazioni informatiche delle moderne economie "dot.com", sono riuscite a innescare processi di sviluppo non solo economico, ma anche politico e sociale. Senza fiducia precipiteremmo in una condizione molto simile allo stato di natura hobbesiano, dove non esistono "arti, né lettere, né società", dove domina "la continua paura ed il pericolo di una morte violenta". Fidarsi significa innanzitutto instaurare una relazione interpersonale e, nell'ambito di essa, operare congiuntamente per il miglioramento dello "status quo". Ma a tale possibilità fa da naturale contraltare il rischio legato al tradimento della fiducia. Fidarsi vuol dire rischiare, ma implica anche indurre gli altri ad essere più affidabili. Qui sta il paradosso: fidarsi significa ridurre il rischio del tradimento. Questo volume esplora attraverso l'analisi economica, con incursioni nei territori della filosofia, della storia delle idee e della psicologia, la rilevanza di tale paradosso per la comprensione e la regolazione dei fenomeni economici e sociali in genere.

Paradoxes of Trust.

Rational Choices and Interpersonal Dynamics

Since the XVI century the role of trust has been recognised as central for social life, as well as for economic and political development. However its apparently transparent character has in many respects revealed illusory. In fact, at a deeper inspection, trust turns out to be an extremely complex issue. Despite their centrality in social sciences, Trust, Trustfulness and Trustworthiness, largely eluded any attempts to be formalised and experi- mentally investigated. This book aims at providing building blocks for an economic theory of trust. It introduces and defends a single hypothesis: trust can be induced by trustworthiness but trustworthiness can also be elicited by trust. This is the simple principle of trust responsiveness. Chapter I defines a trusting interaction and discusses its phenomenology. Chapter II creates a context for the concept of trust by reviewing a great deal of literature in a variety of fields. Philosophy, Politics, Sociology and Legal Theory all pose different questions and face the phenomenon of trust from different viewpoints, looking for different answers. Neverthe- less, their analysis and results share many common features as well as many limitations. These will be the departing point for my argument. First of all I provide precise and operationalizable definitions of trustful and trustworthy behaviour. Secondly I present several examples showing where those behaviours are observed in controlled environments (Chapter III). The existence of trustful and trustworthy behaviour turns out to be a puzzle for standard economic theory. Those behaviours represent, as a matter of fact, both empirical and theoretical anomalies. Then I consider how economics and in particular game theory seeks to resolve that puzzle and to explain those apparent anomalies. The standard game theoretical model is the departing point for the analysis of three different research strategies. Two of them are analysed in Chapter IV; a third in Chapter V. The first strategy introduces elements of complexity into the standard games, such as repetition, reputation and bounded rationality. These models share the common feature of formalising agents’ deliberative process in a consequentialist manner, that is, as based on the comparative assessment of the consequences that different courses of actions yield. The discussion of alternative solutions leads to the individuation of some unsatisfactory implications and limits of the models. Some of them are intrinsic to the adopted explanatory approach, while others are matter of empirical analysis. The second class of models use the standard game theoretical solutions but consider the nature of payoffs as representing not just material motivations; those are models of altruism and inequity aversion. The third class of models can be defined as «procedural», since they consider agents as motivated not only by the consequences their ac- tions lead to but also by the way such consequences are attained. These models differ from the traditional one as they consider players’ payoff as representing something more than a mere material measure of wealth and because they develop different solution concepts. Examples of this kind are team-thinking, normative expectations, and reciprocity models. Chapter VI introduces an alternative principle that may be used as explanans of trustful and trustworthy behaviours: trust responsiveness. From the study of the problem of trust it emerges that the problem can be fully understood only assuming a relational framework. Such a framework describes people’s behaviour as a product of mutual influences which transcend mere individualistic strategic considerations. This Chapter sets a philosophical and historical context for the idea of trust responsiveness that postulates how the subjects are motivated to behave trustworthily from the fact of being the object of others’ trust. This principle assumes that by being trustful A signals to B her expectations about B’s behaviour. In particular A’s trustful behaviour signals to B that A expects B to be trustworthy. This kind of reasoning based on each agent’s own desire for praiseworthiness gives rise of internal and external sources of motiva- tions. In the Chapter the relational factors that characterise the idea of trust responsiveness are utilised to distinguish it sharply from the alternative explanatory principles discussed in earlier Chapters. This discriminatory exercise turns out to be crucial in order to resolve the decomposition problem, that is, the possibility of discriminating among observationally equivalent theories. The intuitions and the philosophical elements defining the idea of trust responsiveness are embodied and formalised in a game theoretical model of trustful and trustworthy behaviours. Such a model is based on psychological game theory and utilises the ideas of forward induction and of strategies as signal of expectations. The psychological equilibrium conditions are derived. In Chapter VIII the book addresses the problem of the empirical relevance of the trust responsiveness hypothesis. Two experiments showing the existence of trust responsive behaviours are discussed and a third original experiment is presented that aims at discriminate among all the explanatory principles introduced so far. The last Chapter deals with the implications of the idea of trust responsiveness for the activity of institutional design. If trustworthiness is, at least in part, a product of trusting behaviour, the relational and interaction schemes of our institutions have to be designed leaving room for the inducing force of trust. Several instruments that can be adopted for this task are discussed: i.e. framing, motivational crowding-in, norm management and the use of the expressive value of law.