Socialmedicinsk tidskrift 3/2018 tema 1 The Impact of Trust on Large-scale Collective Action Sverker C. Jagers and Felicia Robertson Sverker C. Jagers, professor of political science at the University of Gothenburg. Email: sverker.jagers@pol.gu.se Felicia Robertson, PhD candidate in political science at the University of Gothenburg. Email: felicia.robertson@gu.se The ability to engage in collective action has forged the history of humankind, yet it cannot be taken for granted, because if everyone else cooperates, it gives each individual reason to freeride on other people’s accomplishments. Solving major challenges such as antibi- otic resistance and climate change will require a tremendous degree of collective action. In this paper, we discuss the importance of, and the relationship be-tween trust and col- lective action, either on a voluntary basis or through political intervention. By analysing survey data, we find a positive relationship between generalised trust and voluntary col- lective action, while this kind of trust is either negatively related, or not related at all, to people’s acceptability of political steering. We also find a positive relationship between political-institutional trust and acceptability of such steering. Introduction Many of the major challenges that the world is cur- rently facing can be defined as collective action problems (Ostrom, 2010), or cooperation prob- lems. Examples include the climate change prob- lem, over-fishing and pollution of oceans and seas and the growing problem of antibiotic resistance. A collective action problem is usually defined as a situation where the total benefit to a group of peo- ple is maximized when all members of the group cooperate, while each individual in the group de- rives the greatest personal benefit by not cooper- ating or contributing to the collective bene-fit, re- gardless of whether other group members coop- erate or not (Dawes, 1980). Thus, each individual who understands the nature of this problem must make concessions, i.e. must choose to behave in a way that will not yield the greatest possible per- sonal benefit, in order to solve the dilemma at hand. Moreover, the dilemma implies an obvious risk of being taken advantage of by other group members, i.e. a risk of some individuals choosing to make personal sacrifices for the common good while most others choose not to. In effect, the good cooperators risk getting caught in a so-called social trap (Rothstein, 2005). This refers to a situ- ation where an actor chooses to cooperate and give up their immediate self-interest, while other actors continue to act according to their self-inter- est, thus leading to the resource or good in ques- tion continues to deteriorate (Kollock, 1998). Therefore, with the risk of ending up in a social trap, an interesting question in this context is whether – and if so under what conditions – indi- viduals may be willing to cooperate by not acting based on self-interest in order to avoid collective losses. When it comes to small-scale dilemmas, such as local fishing in a small lake, research has shown that certain factors can increase the likelihood of persistent collective action occurring among group members. Such factors include small group size, a low level of anonymity, transparency, good opportunities for communication, recurring inter- action among the actors involved, delimitation of the resource, opportunities to punish non-compli- ance, and trust (Dietz, Dolšak, Ostrom, & Stern, 2002). In contrast, however, the challenges we focus on in the present article are far more large scale in terms of both the size of the problems and the number of actors involved. It is unfortunate that a comparatively small volume of research has been conducted on ways to avoid large-scale collective action problems and in particular the role of trust in this context (cf. Nannestad, 2008; Uslaner, 2000). It seems reasonable to assume that the more large-scale a collective problem is, the more difficult it is to establish the level of collective ac- tion necessary to eliminate it. At the same time, however, we know from history, and in fact from simply looking at our own neighbourhoods and local communities, that such cooperation has al- ways occurred and continues to take place. For