Evaluating Optimality Theory for Pronoun Resolution Algorithm Specification

A recent paper (Beaver, 2004) recasts the Centering algorithm for pronoun resolution (Brennan et al., 1987) in terms of optimality theory (OT). Although the limitations of centering for pronoun resolution are well known, the algorithm's restatement in OT highlights the strengths of centering and produces an algorithm whose behavior is more transparent to the developer. The authors' motivation for developing this algorithm was due to the software engineering characteristics of OT as a specification mechanism, rather than improved pronoun resolution performance. There has been little previous work marrying computational pronoun resolution work with OT. Therefore, this study reports our experience implementing the OT formulation of centering in order to evaluate its desirability as a pronoun resolution specification formalism. Although the expressive capability of OT has some limitations, the benefits of the OT formalism are worth some attention. This paper seeks to highlight those benefits, and indicate how they can be employed within pronoun resolution algorithms, whether or not an OT formalization is employed.