The Logical Dynamics of Gossip: an analysis in Dynamic Epistemic Logic
Rana Klein

Abstract:
This thesis gives a formal logical analysis of a social phenomenon; gossip. Gossip can be used to serve many goals. The Sherlock Holmes’ of our society -always looking for an explanation- might use gossip to find an explanation for a surprising observation. Also for the agents that are not so eager to find the truth, for those who are more concerned about their social position instead, gossip might be helpful. Gossip can be used as a tool to exclude or include a specific person from a group. Further, gossip can help to increase or decrease the social bonding within a group. An agent might start to gossip in order to reach any of these goals. Each of them gives the gossip conversation a different structure. This work formally describes and models the epistemic and social sides of gossip and proceeds by giving formal protocols that correspond to a number of different conversation structures. In the formal part we use dynamic epistemic logic, which is able to model the changes in the knowledge and beliefs of agents. In order to deal with the changes in the network relations, we add a social network structure to each epistemic state as well as actions that change those network structures.