Single‐Stage Prediction Models Do Not Explain the Magnitude of Syntactic Disambiguation Difficulty
Single‐Stage Prediction Models Do Not Explain the Magnitude of Syntactic Disambiguation Difficulty
复制标题
单阶段预测模型无法解释句法消歧困难的严重程度
DOI：
10.1111/cogs.12988
复制
发表时间：
2021
影响因子：
2.5
通讯作者：
Linzen, Tal
中科院分区：
文献类型：
--
作者：
van Schijndel, Marten;Linzen, Tal
对句法上有歧义的句子进行消歧以支持较不优选的解析可能导致在消歧点处较慢的阅读。这种现象，被称为花园小径效应，有动机的模型，其中读者最初只维护句子的可能解析的子集，随后需要耗时的重新分析来重建丢弃的解析。最近的一个提议认为，花园小径效应可以简化为完全并行解析器中出现的重复：与最初不正确但最终正确的解析相一致的单词比与不正确解析相一致的单词更难预测。由于可预测性在阅读中的影响远远超出了花园小径的句子，因此这种无需再分析机制的解释更为简洁。至关重要的是，它预测了一个线性效应：花园小径效应预计将与最终正确和最终不正确的解释之间的单词重复性差异成比例。为了测试这一预测，我们使用递归神经网络语言模型来估计三个暂时模糊的结构的逐字翻译。然后，我们根据人类自定节奏的阅读时间估计了每一个音节的减速，并使用该数量来预测句法消歧的难度。Surprisal成功地预测了花园小径效应的存在，但大大低估了它们的大小，并且未能预测它们在建筑物中的相对严重程度。我们的结论是，句法消歧困难的充分解释可能需要超出可预测性的恢复机制。
The disambiguation of a syntactically ambiguous sentence in favor of a less preferred parse can lead to slower reading at the disambiguation point. This phenomenon, referred to as a garden‐path effect, has motivated models in which readers initially maintain only a subset of the possible parses of the sentence, and subsequently require time‐consuming reanalysis to reconstruct a discarded parse. A more recent proposal argues that the garden‐path effect can be reduced to surprisal arising in a fully parallel parser: words consistent with the initially dispreferred but ultimately correct parse are simply less predictable than those consistent with the incorrect parse. Since predictability has pervasive effects in reading far beyond garden‐path sentences, this account, which dispenses with reanalysis mechanisms, is more parsimonious. Crucially, it predicts a linear effect of surprisal: the garden‐path effect is expected to be proportional to the difference in word surprisal between the ultimately correct and ultimately incorrect interpretations. To test this prediction, we used recurrent neural network language models to estimate word‐by‐word surprisal for three temporarily ambiguous constructions. We then estimated the slowdown attributed to each bit of surprisal from human self‐paced reading times, and used that quantity to predict syntactic disambiguation difficulty. Surprisal successfully predicted the existence of garden‐path effects, but drastically underpredicted their magnitude, and failed to predict their relative severity across constructions. We conclude that a full explanation of syntactic disambiguation difficulty may require recovery mechanisms beyond predictability.