Susanne Lohmann, “The dynamics of informational cascades: The Monday demonstrations in Leipzig, East Germany, 1989–91”, World Politics 47: 42–101 .

Summary: Lohmann examines the collapse of the East German regime given the dual observations that the collaps was both a surprise and an inevitability. Her main contention is that the regime was able to control access to key information about the nature (and the weakness) of the regime, that once revealed led to its downfall.  The demonstrations that occurred in Leipzig carried this information – they were signals to the population about predominant viewpoints within the populace, and triggered an ‘‘informational cascade’’ which undermined the viability of the regime.  Lohmann examines the dominant theories for how dissatisfaction shifts to mass protest (theory of relative deprivation and the theory of political opportunity structure) but finds them lacking in light of the informational cascade model of mass political action.  In essence, this model proposes the following: that each individual has imperfect information, but as an aggregate the population is well informed; that the masses take their informational cue from the simple signal of aggregate turnout to demonstrations; that a costly political action can be thought of as a costly contribution to the public good of information; and finally, that the receivers’ interpretation of the signals transmitted by the senders depends on the conflict of interest between the senders and the receivers.  Given this model, and given that individuals in a controlled regime have access to very little information, much can and is made of the aggregate participation statistic. This explains why the regime survived so long, and also why it fell so quickly.

Important Insight: The information provided by the aggregate statistic of participation in demonstrations alters the individuals expected costs of participation in future demonstrations

Methodology: A rational choice argument based on signalling and information accessibility