The syntactic structure of a sentence can be represented as a graph where vertices are words and edges indicate syntactic dependencies between them. In this setting, the distance between two syntactically linked words can be defined as the difference between their positions. Here we want to contribute to the characterization of the actual distribution of syntactic dependency distances, and unveil its relationship with short-term memory limitations. We propose a new double-exponential model in which decay in probability is allowed to change after a break-point. This transition could mirror the transition from the processing of words chunks to higher-level structures. We find that a two-regime model -- where the first regime follows either an exponential or a power-law decay -- is the most likely one in all 20 languages we considered, independently of sentence length and annotation style. Moreover, the break-point is fairly stable across languages and averages values of 4-5 words, suggesting that the amount of words that can be simultaneously processed abstracts from the specific language to a high degree. Finally, we give an account of the relation between the best estimated model and the closeness of syntactic dependencies, as measured by a recently introduced optimality score.
翻译:句子的合成结构可以作为图表来表示, 脊椎是单词, 边缘是它们之间的共性依赖性。 在这种背景下, 两个相互关联的词之间的距离可以被定义为其位置之间的差别。 在这里, 我们想帮助描述同义依赖距离的实际分布, 并展示它与短期内存限制的关系。 我们提出了一个新的双重实验模型, 允许断点后发生衰变的可能性。 这一过渡可以反映从处理字块到更高层次结构的过渡。 我们发现, 两种制度模式 -- -- 第一个制度要么是指数性,要么是权力法衰变 -- 最有可能是我们所考虑的所有20种语言中的一种, 与句长和注解风格无关。 此外, 断点在语言和平均值4-5字之间相当稳定, 表明可以同时处理的词汇数量从特定语言到高度。 最后, 我们给出了两个制度模式的关系, 第一个制度要么是指数性,要么是指数性衰减,要么是权力法衰减, 可能是我们所考虑的所有20种语言中的一种。 此外, 断点在语言和平均值4-5字数值之间相当稳定, 表明, 可以同时处理的词数从特定语言到高度。 我们给出了最近所测量的模型和最接近的精确度之间的关系。