# Fairness and Trust in Virtual Environments: The Effects of Reputation
## 2 Introduction  
Fairness, trust and social influence dynamics have received an increasing attention in relation to virtual environments in latest years. In fact, these constructs appear to play a fundamental role in a plethora of virtual social interactions, e.g., e-market, virtual workgroups, crowdsourcing [1; 2]. In virtual environments \"reputational systems\" have been widely used because of their capability to positively impact the aforementioned psychosocial dynamics. Nevertheless, a model explaining the potential impact of such systems in affecting online human dynamics, for instance within a social dilemma situation (i.e., where individuals have conflicting interests), is still missing. Our study shows that in a virtual environment the introduction of a reputational system, structured to be independent and not affecting the goal given to the subjects, has a significant impact on the decision dynamics (i.e., the problem solving strategies) adopted by the players. In particular, when the reputational system was present we observed an increasing in the fairness and trust levels, as well as in the players' average social influence on the others. We also found age-related differences in reputation usage (i.e., adolescents avoided asking information to bad and ambiguous reputed individuals), and management (i.e., adolescents obtained a lower level of reputation overall), while gender effects appeared quite small. _Reputation Effects on Prosocial Behaviors between Real and Virtual Environment_  
Fairness and trust are two important aspects of social interactions. A concern for relative payoffs between oneself and another individual, and the willingness to rely on someone's help or suggestion are important aspects of social exchanges [3; 4]. Understanding why and how humans act pro-socially is a challenging question, and several mechanisms have been proposed among which reputation has gained important recognition in the last decade [5; 6; 7; 8]. Computational models [9; 10], and laboratory experiments [11; 12; 13], emphasize the role of reputation as a motive supporting pro-social behaviours through indirect reciprocity [14]. Indeed, reputation allows to discriminate between pro-social and selfish individuals through informal and inexpensive social control [15; 16; 17], and thanks to gossip cheaters can be identified, and their selfish choices punished [18]. Interestingly, reputation still influences people's decision making even when it comes from a complete unknown source and it is earned from an obscure situation [19]. Analogously, in online markets information sharing is a powerful means to build trust and enforce norms [20], and reputation systems based on online feedback mechanisms [21] make possible to have large scale interactions between complete strangers living in faraway places. Moreover, the information and communication technologies (ICT) revolution introduced brand new factors affecting trust and reputation dynamics impacting on both cyber communities as well as real ones [22; 23; 24; 25]. In particular, very recent research highlights how a transaction could be completed in virtual environments because of reputation, even in the absence of any other enforcement [26]. Reputation can be considered as a collective phenomenon and a product of social processes [27], that goes well beyond single beliefs of impressions in the mind of any single individual. We can think of reputation as a product of natural evolution that equips human groups with a higher collective intelligence potential. In such sense, reputation is an evolutionarily stable strategy [17] that fosters the emergence and maintenance of pro-social behaviours. Not surprisingly, humans learn very early how to handle reputation during their development. The progressive achievement of a complete Theory of Mind [28; 29], and the maturation of the reward system [30] might provide the bases for the development of a capacity to track others' reputation and to manage one's own.