|dc.description.abstract||It is a well-documented social dilemma that as the size of a group increases, individual members of the group are incentivized to contribute less effort towards group tasks. This phenomenon has many names, including social loafing, group motivation loss, and the free- riding effect. This presents a problem across collaborative crowd sourcing, fundraising drives, and group tasks in general. Various mechanisms have been shown to be successful in induc- ing cooperation, such as group rewards for crossing total contribution thresholds or pitting groups against each other in competitive settings, and offering a reward to the winner. It has been suggested that each of these mechanisms works by appealing to self-interested in- centives, making increased effort and contribution the strategy which maximizes individual payout. However, recent work has implied that there are psychological mechanisms which push humans to cooperate even when it is not of tangible self-interest, and that these mech- anisms are particularly strong in settings which are competitive at the intergroup level.
In this thesis, we show that the free-riding effect still exists in the equilibrium of cooper- ative games which are competitive at the intergroup level through the use of game theoretic analysis. However, we go on to show through the use of an online lab experiment of our own design that when humans play the same game, their behavior does not exhibit a significant free-riding effect. For comparison, we use a non-competitive threshold game, and show that in this setting, the free-riding effect still persists and we see lowered levels of contribution as team size grows, although this effect dissolves for teams of size 6 and larger. Our results suggest that there are psychological mechanisms in humans which specifically counteract the free-riding effect. Furthermore, our results suggests that these mechanisms exist specifically in scenarios which are competitive at the intergroup level.||