Limited-Trust in Social Network Games

TL;DR

This paper models trustworthiness in social network games, showing that agents tend to become more trustworthy through interactions, which increases overall utility, but trustworthiness decreases when opportunities are plentiful.

Contribution

It introduces a game-theoretic model of limited-trust in social networks and demonstrates how trustworthiness evolves and impacts utility through empirical simulations.

Findings

Trustworthy agents increase overall utility by up to 14.5%.

Agents can boost their utility by up to 25% by being modestly trustworthy.

Trustworthiness decreases when partnership opportunities are abundant.

Abstract

We consider agents in a social network competing to be selected as partners in collaborative, mutually beneficial activities. We study this through a model in which an agent i can initiate a limited number k_i>0 of games and selects the ideal partners from its one-hop neighborhood. On the flip side it can accept as many games offered from its neighbors. Each game signifies a productive joint economic activity, and players attempt to maximize their individual utilities. Unsurprisingly, more trustworthy agents are more desirable as partners. Trustworthiness is measured by the game theoretic concept of Limited-Trust, which quantifies the maximum cost an agent is willing to incur in order to improve the net utility of all agents. Agents learn about their neighbors' trustworthiness through interactions and their behaviors evolve in response. Empirical trials performed on realistic social networks show that when given the option, many agents become highly trustworthy; most or all become highly trustworthy when knowledge of their neighbors' trustworthiness is based on past interactions rather than known a priori. This trustworthiness is not the result of altruism, instead agents are intrinsically motivated to become trustworthy partners by competition. Two insights are presented: first, trustworthy behavior drives an increase in the utility of all agents, where maintaining a relatively modest level of trustworthiness may easily improve net utility by as much as 14.5%. If only one agent exhibits modest trust among self-centered ones, it can increase its average utility by up to 25% in certain cases! Second, and counter-intuitively, when partnership opportunities are abundant agents become less trustworthy.