Publications by Author: Curtis S. Signorino

The pattern of alliance commitments among states is commonly assumed to reflect the extent to which states have common or conflicting security interests. For the past twenty years, Kendall's tau–b has been used to measure the similarity between two nations' "portfolios" of alliance commitments. Widely employed indicators of systemic polarity, state utility, and state risk propensity all rely upon tau–b. We demonstrate that tau–b is inappropriate for measuring the similarity of states' alliance commitments. We develop an alternative measure of alliance portfolio similarity, S which avoids many of the problems associated with tau– b, and we use data on alliance among European states to comparare the effects of S versus tau–b in measures of utility and risk propensity. Finally, we identify several problems with inferring state interest from alliance commitments and we provide a method to overcome those problems using S in combination with data on alliance, trade , UN votes, diplomatic missions, and other types of state interaction. We demonstrate this by comparing the calculated "similarity of interests" when using solely alliance data versus that using alliance data supplemented with UN voting data.

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The repeated Prisoner's Dilemma is representative of a broad range of situations in international relations, both in security and in international political economy. Of particular interest to international relations theorists is the evolution of cooperati on among states under such conditions. In contrast to past research, which has either not incorporated the possibility of implementation or perception errors or has incorporated only a symmetric form of those errors, I examine the effects of asymmetric "noise" on the emergence and maintenance of cooperation in a repeated Prisoner's Dilemma. I find that positive and negative asymmetric noise have very different effects on the strategies' performances in the systems modeled here and that the effects of neutral noise reflect the signature effects of each asymmetric noise type. Of the strategies examined, Contrite Tit–for–Tat (CTFT) proves to be a robust heuristic across all noise environments, with generally superior performance in the heterogeneous systems and in the evolutionary models. CTFT as an institution is also robust across all noise environments and, under the conditions of this study, actors will almost always fare better in a CTFT institution than by employing any other strategy in a heterogeneou s system. Thus, there are incentives for the formation of institutions — and, in fact, one sees the boundedly-rational actors of the evolutionary models moving from heterogeneous modes of bilateral interaction to cooperative norms of behavior..

Available in print format only.