Given a sentence "Abby told Brittney that she upset Courtney", one would struggle to understand who "she" refers to, and ask for clarification. However, if the word "upset" were replaced with "hugged", "she" unambiguously refers to Abby. We study if modern coreference resolution models are sensitive to such pronominal ambiguity. To this end, we construct AmbiCoref, a diagnostic corpus of minimal sentence pairs with ambiguous and unambiguous referents. Our examples generalize psycholinguistic studies of human perception of ambiguity around particular arrangements of verbs and their arguments. Analysis shows that (1) humans are less sure of referents in ambiguous AmbiCoref examples than unambiguous ones, and (2) most coreference models show little difference in output between ambiguous and unambiguous pairs. We release AmbiCoref as a diagnostic corpus for testing whether models treat ambiguity similarly to humans.

翻译：[translated abstract in Chinese] 给定句子"Abby告诉Brittney她惹恼了Courtney"，人们难以判断"她"的所指对象并需要澄清。然而，若将"惹恼"替换为"拥抱"，则"她"明确指向Abby。本研究探究现代共指消解模型是否对此类代词歧义具有敏感性。为此，我们构建了包含歧义与无歧义指代的最小句对诊断语料库AmbiCoref。例句泛化了关于特定动词及其论元排列对人类歧义感知的心理语言学研究。分析表明：(1)人类对AmbiCoref歧义示例中指代对象的确定性低于无歧义示例；(2)大多数共指消解模型在歧义与无歧义句对间的输出差异极小。我们发布AmbiCoref作为诊断语料库，用于检验模型是否以类人方式处理歧义现象。