A game theoretical model for collaborative groups in social applications

• Proposing an analytical model for collaborative groups based on repeated game theory.
• Simulating participants’ behaviours using different existing Tit for Tat strategies.
• Analysing the impact of the free riders in collaborative groups survivability.
• Proposing the group reputation tit for tat strategy to motivate free riders.

In this paper, we address the problem of the free riding behaviour that takes advantage of collaborative educational social groups without contributing back to other participants posts. Free riders are active users who ask questions and draw knowledge from the community but provide very limited or no contributions back to it. Since the survival of a collaborative educational community is highly dependent on its active users and their contributions, motivating free riding users to take an active part would naturally augment the value the community provides and ensure its survivability. As a solution, we formally analyse the impact of the free riding behaviour by means of repeated game theory where classical and generous Tit for Tat are used. Such analysis shows the impact of such behaviour on educational communities and raises the need for other strategies that motivate free riding users to cooperate under the threat of being punished by cooperative ones; hence, we introduce reputation based Tit for Tat strategies. Our study suggests adding reputation as a parameter in users’ profiles in collaborative groups to improve their survivability.