The tragedy of the risk perception commons



An interesting theory of risk perception and communication is put forward by Kahan (2012) in the context of climate risk.

Kahan et al argue that in belonging to a peer group, going against the common opinion can cost the individual while having little real effect upon the group’s collective opinion. So in the end it is better for individuals to simply shut up when convinced of a contrary opinion rather than attempting to change group behaviour. They call this the ‘tragedy of the risk-perception commons’, which is a tip of the hat to Garret Hardin’s original 1960s work that showed how individuals acting rationally in their own self interest could produce a collective failure.

This is an example of what economists call Games Theory and sociologist call the Theory of Social Situations, in fact Kahan’s example (and Hardin’s original study) can be classified as a variant of the canonical prisoners dilemma. What I find interesting is how the study once again undermines the idea of a perfect and objective risk perception methodology. Risk communication and perception it seems are also subject to competitive forces amongst individuals.


Kahan, D.M, Peters, E., Wittlin, M., Slovic, P., Ouellette, L.L., Brahman, D., Mandel, G., The polarizing impact of science literacy and numeracy on perceived climate change risks, Nature Climate Change (2012) doi:10.1038/nclimate1547, Published online 27 May 2012.

3 responses to The tragedy of the risk perception commons


    This also seems to me like a descrition of the social/personal dynamic of Group Think (Janis) which can, at extremes, lead to a phenomenon called Risky Shift, where peers feel emboldened by the lack of critique to put forward a more extreme point of view (either greater risk or more risk averse). This can bootstrap itself into a group accepting extreme positions and acting with very poor judgement.

    See, for example


      Matthew Squair 18/06/2012 at 4:40 pm

      I think that the undelying psychological factors are the same in both cases (the human need to be accepted) but the context, mechanisms and end effects are different.

      In Groupthink the context is a cohesive decision making group and within that context (as I understand it) it’s possible that group members actually end up accepting uncritically the groups viewpoint. See Janis’ original definition, “…members’ strivings for unanimity override their motivation to realistically appraise alternative courses of action.”.

      In this instance it’s the maintenance of a dissenting group member’s social status through silence that chills public discussion rather than a cohesiveness driven conforming of opinion that’s at work. Elisabeth Noelle Neumann’s concept of the Spiral of Silence might be a better fit to this context.

      The two mechanisms as I see it are inter-twined, for example in Groupthink it’s likely that dissenters are ‘driven out’ which reinforces actual conformity and also warns an individual of the personal consequences of non-conformity, that results finally in the absence of any counter viewpoint within the group.



    Thank you for introducing me to the Spiral of Silence – I think this explains your observations well and it is a concept that is new to me.

    However, I wonder if the real key to the Kahan et al paper is the endorsement it provides for the definitions within the cultural theory of risk: that the hierarchical world-view perceives risks as subordinate to an all-important set of societal structures. In this case, we would expect a highly scientifically literate individual to ‘argue their way out of’ any perceived risk in order to avoid any disruptive consequences for their precious societal status quo.

    They need to allay cognitive dissonance must either acknowledge the threat and abandon the primacy of society or diminish the threat to protect society from disruptive change. This is what the authors saw.